A Journey 2 Eternity

Painting a Gradient background

2009-06-08T18:11:00.002+06:00

Here’s a sample which draws background of a dialog with gradient colors.

BOOL CMyDlg::OnEraseBkgnd(CDC* pDC)
{
CRect rect;
GetClientRect(&rect);

TRIVERTEX vert[4] = {
{ rect.left, rect.top, 0xff00, 0xff00, 0xff00, 0 },
{ rect.right, rect.top, 0, 0xff00, 0xff00, 0 },
{ rect.right, rect.bottom, 0xff00, 0, 0xff00, 0 },
{ rect.left, rect.bottom, 0xff00, 0xff00, 0, 0 }
};

GRADIENT_TRIANGLE grad[2] = {
{ 0, 1, 2 },
{ 0, 2, 3 }
};

::GradientFill( pDC->m_hDC, vert, 4, grad, 2, GRADIENT_FILL_TRIANGLE );

return TRUE;
}

void CMyDlg::OnSize(UINT nType, int cx, int cy)
{
// To ensure the background of the whole dialog is re-drawn
Invalidate();

CDialog::OnSize(nType, cx, cy);
}

Replaces a color with a fill color in a given area of a Device Context

2009-05-28T16:47:00.004+06:00

//! Replaces a color with a fill color in a given area of a
//! Device Context
//!
//! \param hDC : Specifies the Device Context
//! \param rcReplaceArea : Specifies the portion of the DC area
//! to apply the replace operation
//! \param clrColorReplace : Specifies the color to be replaced
//! \param clrColorFill : Specifies the fill color

void ReplaceColor(HDC hDC, CRect rcReplaceArea, COLORREF clrColorReplace,
COLORREF clrColorFill)
{
CDC* pDC = CDC::FromHandle(hDC);

CPoint pt = rcReplaceArea.TopLeft();

CDC memDCMonoChrome;
memDCMonoChrome.CreateCompatibleDC(pDC);
CBitmap bmpMonoChrome;
bmpMonoChrome.CreateCompatibleBitmap(&memDCMonoChrome,
rcReplaceArea.Width(), rcReplaceArea.Height());
CBitmap* pOldMonoBitmap =
memDCMonoChrome.SelectObject(&bmpMonoChrome);

COLORREF nOldBkColor = pDC->SetBkColor(clrColorReplace);
// BLT to mono dc so that mask color will have 1 set and the other colors 0
memDCMonoChrome.BitBlt(0, 0, rcReplaceArea.Width(),
rcReplaceArea.Height(), pDC, pt.x, pt.y, SRCCOPY);

CDC memDC;
memDC.CreateCompatibleDC(pDC);
CBitmap bmp;
bmp.CreateCompatibleBitmap(pDC, rcReplaceArea.Width(),
rcReplaceArea.Height());
CBitmap* pOldBitmap = memDC.SelectObject(&bmp);

COLORREF nOldMemDCBkColor = memDC.SetBkColor(clrColorFill);
COLORREF nOldMemDCTextColor =
memDC.SetTextColor(RGB(255, 255, 255));
// BLT to mem DC so that the monochrome white is set to fill color and the
// monochrome black is set to white
memDC.BitBlt(0, 0, rcReplaceArea.Width(), rcReplaceArea.Height(),
&memDCMonoChrome, 0, 0, SRCCOPY);

// AND pDC with mem dc so that the replace color part is blackened out and
// all other colors remains same
pDC->BitBlt(pt.x, pt.y, rcReplaceArea.Width(), rcReplaceArea.Height(),
&memDC, 0, 0, SRCAND);

memDC.SetTextColor(RGB(0, 0, 0));
// BLT to mem DC so that the monochrome white is set to fill color and the
// monochrome black is set to black
memDC.BitBlt(0, 0, rcReplaceArea.Width(), rcReplaceArea.Height(),
&memDCMonoChrome, 0, 0, SRCCOPY);

// OR pDC with mem dc so that all colors remains as they where except the
// blackened out (replace color) part receives the fill color
pDC->BitBlt(pt.x, pt.y, rcReplaceArea.Width(), rcReplaceArea.Height(),
&memDC, 0, 0, SRCPAINT);

// Set the original values back
memDC.SetTextColor(nOldMemDCTextColor);
memDC.SetBkColor(nOldMemDCBkColor);

pDC->SetBkColor(nOldBkColor);

// Set the original bitmaps back
memDCMonoChrome.SelectObject(pOldMonoBitmap);
memDC.SelectObject(pOldBitmap);
}

Sequence of messages sent on Double Click Event

2009-05-19T14:52:00.001+06:00

1. LButtonDown
2. LButtonUp
3. LButtonDblClick
4. LButtonUp

Wild-Card Comparison

2009-05-13T16:28:00.001+06:00

Sometimes we have needed to compare a Wild-Card string in a given string. Here is a handy function for doing this:

int WildCmp(const TCHAR* wild, const TCHAR* string)

{

const TCHAR *cp = NULL, *mp = NULL;

while ((*string) && (*wild != '*'))

{

if ((*wild != *string) && (*wild != '?'))

{

return 0;

}

wild++;

string++;

}

while (*string)

{

if (*wild == '*')

{

if (!*++wild)

{

return 1;

}

mp = wild;

cp = string+1;

}

else if ((*wild == *string) || (*wild == '?'))

{

wild++;

string++;

}

else

{

wild = mp;

string = cp++;

}

while (*wild == '*')

{

wild++;

}

return !*wild;

}

Draw vertically centered multi-line text in a given rectangle

2009-04-22T12:09:00.000+06:00

DT_WORDBREAK and DT_VCENTER don’t work together. So here is an alternative:

void CEMCHotButton::DrawCaption (CDC* pDC, LPDRAWITEMSTRUCT

lpDrawItemStruct, CRect& rectCaption, DWORD dwFormat)

{

// Get caption text

CString strCaption;

GetWindowText (strCaption);

if(!strCaption.IsEmpty())

{

if((GetStyle() & BS_MULTILINE) == BS_MULTILINE)

{

dwFormat &= ~DT_SINGLELINE;

dwFormat &= ~DT_VCENTER;

dwFormat |= DT_WORDBREAK;

RECT rct = rectCaption;

int height = ::DrawText(pDC->m_hDC, (LPCTSTR) strCaption, strCaption.GetLength(), &rct, DT_CALCRECT | DT_WORDBREAK);

rectCaption.top = rectCaption.CenterPoint().y - height / 2;

::DrawTextEx (pDC->m_hDC, strCaption.GetBuffer(0),

strCaption.GetLength(), &rectCaption,

dwFormat, NULL);

}

How to create a topmost window using SetWindowPos?

2009-04-15T13:10:00.000+06:00

A topmost window is one which stays on top of other windows even while it’s not in focus. Normally all application popup windows will go to background once they lose focus but a topmost window doesn’t.

void SetTopMost( HWND hWnd, const BOOL TopMost )

{

ASSERT( ::IsWindow( hWnd ));

HWND hWndInsertAfter = ( TopMost ? HWND_TOPMOST : HWND_NOTOPMOST );

::SetWindowPos( hWnd, hWndInsertAfter, 0, 0 , 0 , 0,

SWP_NOMOVE | SWP_NOSIZE );

}

The second parameter passed to ::SetWindowPos is the one that does the trick. It’ called hwndInsertAfter, if we specify the after window as HWND_TOPMOST then we get a topmost window, if we specify after window as HWND_NOTOPMOST then topmost setting is unset and our window becomes a normal window.

Set resource handle in MFC and ATL

2009-04-15T12:38:00.000+06:00

When working in MFC/ATL and then using a resource dll can at times cause bugs because resource handle is not properly set. For e.g. if you have a dialog resource in a dll and you instantiate a CDialog which results in an error because resource cannot be located in this application or dll since it’s in the resource dll. So solution for above problem will be to set correct resource handle.

MFC provides two functions…

1. AfxGetResourceHandle

2. AfxSetResourceHandle

So we should first save our current resource handle and then set new resource handle before loading such a resource. Also don’t forget to set our old handle since its good practice.

Internally MFC calls FindResource and LoadResource using this handle, so if it’s not properly set this will cause failure in loading resources.

In ATL it’s quite similar except that we’ve got a new function called AddResourceInstance which adds our new resource handle to existing list of handles. So when a look up is done given resource handle is also used. Following functions are provided in ATL to work with resource handles…

1. AddResourceInstance

2. GetResourceInstance - Similar to AfxGetResourceHandle

3. SetResourceInstance - Similar to AfxGetSetResourceHandle

For newbies this is always a painful bug to resolve as they don’t know what went wrong since they expect this to be automagically done.

Sample code snippet:

class CEMCResourceHandle

{

public:

CEMCResourceHandle()

{

m_hPrevInst = AfxGetResourceHandle();

m_hDLLInstance = ::LoadLibrary(szESIMFCControlsDLLName);

if (m_hDLLInstance)

{

AfxSetResourceHandle(m_hDLLInstance);

}

virtual ~CEMCResourceHandle()

{

AfxSetResourceHandle(m_hPrevInst);

if(m_hDLLInstance != NULL)

{

FreeLibrary(m_hDLLInstance);

}

//! Retrieves the current resource instance

//!

//! \return Return the current resource instance

HINSTANCE GetCurrentInstance() const { return m_hDLLInstance; }

//! Retrieves the previous resource instance

//!

//! \return Return the previous resource instance

HINSTANCE GetPrevInstance() const { return m_hPrevInst; }

private:

//! Handle of previous resource instance

HMODULE m_hPrevInst;

//! Handle of loaded DLL resource instance

HMODULE m_hDLLInstance;

};

// Just made an temporary instance of CEMCResourceHandle class

// Load resource from the DLL

CEMCResourceHandle resHandle;

// Set bitmap to the MoveUp button

m_btnUp.SetBitmap(::LoadBitmap(resHandle.GetCurrentInstance(),

MAKEINTRESOURCE(IDB_BITMAP_UPARROW)));

Getting an ITEMIDLIST For a Path

2009-04-15T12:02:00.001+06:00

If you have ever used ShBrowseForFolder(), you've probably noticed the pidlRoot member of the BROWSEINFO structure. It can be used to set the "root" folder to browse from. It's usually set to NULL, which means the "Desktop" folder.

Ever wanted to use another folder as the root for the "Browse For Folder" common dialog, but didn't know how to create an ITEMIDLIST for a given path? Here's a function that does it.

BOOL GetItemIdListFromPath (LPWSTR lpszPath, LPITEMIDLIST *lpItemIdList)

{

LPSHELLFOLDER pShellFolder = NULL;

HRESULT hr;

ULONG chUsed;

// Get desktop IShellFolder interface

if (SHGetDesktopFolder (&pShellFolder) != NOERROR)

return FALSE; // failed

// convert the path to an ITEMIDLIST

hr = pShellFolder->ParseDisplayName (

NULL, // owner window

NULL, // reserved (must be NULL)

lpszPath, // folder name

&chUsed, // number of chars parsed

lpItemIdList, // ITEMIDLIST

NULL // attributes (can be NULL)

);

if (FAILED(hr))

{

pShellFolder->Release();

*lpItemIdList = NULL;

return FALSE;

}

pShellFolder->Release();

return TRUE;

} // GetItemIdListFromPath

It's written in C++, but converting it to plain C is just a matter of changing a couple of lines. To do it, change all interface calls like: pShellFolder->ParseDisplayName() to pShellFolder->lpVtbl->ParseDisplayName(pShellFolder, ...), and similar changes to other calls.

Two things: The function receives the path as a UNICODE (LPWSTR) string, so you'll have to convert ANSI strings to unicode using MultiByteToWideChar() before calling the function. Finally, remember that you should free the memory referenced by the pointer to the ITEMIDLIST you get from the function by calling the Free() method of the IMalloc interface, which you can get using SHGetMalloc().

Is a path shared?

2009-04-15T11:57:00.001+06:00

BOOL IsPathShared( LPCTSTR lpctszPath_i )

{

SHFILEINFO shFileInfo = { 0 };

return ( SHGetFileInfo( lpctszPath_i,

&shFileInfo,

sizeof( shFileInfo ),

SHGFI_ATTRIBUTES ) &&

( shFileInfo.dwAttributes & SFGAO_SHARE )

== SFGAO_SHARE );

}// End IsPathShared

Is a given file shortcut to some other file?

2009-04-15T11:55:00.000+06:00

BOOL IsShortcut( LPCTSTR lpctszPath_i )

{

SHFILEINFO shFileInfo = { 0 };

return (( SHGetFileInfo( lpctszPath_i,

&shFileInfo,

sizeof( shFileInfo ),

SHGFI_ATTRIBUTES )) &&

( shFileInfo.dwAttributes & SFGAO_LINK ) == SFGAO_LINK );

}// End IsShortcut

How to resolve a shortcut!

2009-04-15T11:51:00.000+06:00

Ever wondered how to resolve a shortcut! There is a hidden helper function if you are using MFC, it’s called AfxResolveShortcut. I customized it a bit, so that we can use it independently without MFC, and here is the finished product.

BOOL ResolveShortcut( HWND hWnd_i, LPCTSTR lpctszFileIn_i, LPTSTR lptszFileOut_o, const int nPathLength_i )

{

// Object for resolving link

IShellLink* psl = NULL;

*lptszFileOut_o = 0; // assume failure

if (!hWnd_i)return FALSE;

SHFILEINFO info;

if (( SHGetFileInfo(lpctszFileIn_i, 0,

&info, sizeof(info),

SHGFI_ATTRIBUTES) == 0) ||

!(info.dwAttributes & SFGAO_LINK))

{

return FALSE;

}

CoInitialize( 0 );

// Create instance

HRESULT hCreateRes =

CoCreateInstance(

CLSID_ShellLink, 0,

CLSCTX_INPROC_SERVER,

IID_IShellLink,

reinterpret_cast( &psl ));

if ( FAILED( hCreateRes ) || psl == NULL )

{

return FALSE;

}

IPersistFile *ppf = NULL;

if (SUCCEEDED(psl->QueryInterface(IID_IPersistFile, (LPVOID*)&ppf)))

{

USES_CONVERSION; // T2COLE needs this

if ( ppf != NULL &&

SUCCEEDED(

ppf->Load( T2COLE( lpctszFileIn_i ),

STGM_READ))

)

{

/* Resolve the link, this may post UI to find the link */

if ( SUCCEEDED(psl->Resolve( hWnd_i, SLR_ANY_MATCH)))

{

psl->GetPath(lptszFileOut_o, nPathLength_i, NULL, 0);

ppf->Release();

psl->Release();

CoUninitialize();

return TRUE;

}

if (ppf != NULL) ppf->Release();

}

psl->Release();

CoUninitialize();

return FALSE;

}// End ResolveShortcut

//Lets test the above code...

int main()

{

TCHAR chBuffer[MAX_PATH] = { 0 };

ResolveShortcut( hSomeWindow,

_T( "C:\\shortcut to msdev.lnk" ),

chBuffer,

MAX_PATH );

MessageBox( hSomeWindow, chBuffer,

_T( "Hurray shortcut resolved" ),

MB_OK | MB_ICONINFORMATION );

return 0;

}// End main

ComboBox with no borders

2008-12-18T16:18:00.000+06:00

void CMyComboBox::OnPaint()

{

CPaintDC dc(this);

CRect rect;

GetClientRect(rect);

// draw borders

dc.Draw3dRect(rect,

::GetSysColor(COLOR_3DSHADOW),

::GetSysColor(COLOR_BTNHIGHLIGHT));

rect.DeflateRect(1,1);

dc.Draw3dRect(rect,

::GetSysColor(COLOR_3DDKSHADOW),

::GetSysColor(COLOR_BTNFACE));

rect.DeflateRect(1,1);

if( (GetStyle() & 0x0000000f) > CBS_SIMPLE)

{

CRect rectBtn=rect;

rectBtn.left = rectBtn.right - ::GetSystemMetrics(SM_CXHTHUMB);

BOOL bPressed=FALSE;

if(GetKeyState(VK_LBUTTON) <>

{

CPoint point;

::GetCursorPos(&point);

ScreenToClient(&point);

if(rectBtn.PtInRect(point))

{

bPressed=TRUE;

}

// draw button

UINT uState = DFCS_SCROLLDOWN;

uState |= (bPressed ? DFCS_FLAT | DFCS_PUSHED : 0);

dc.DrawFrameControl(rectBtn, DFC_SCROLL, uState );

rect.right=rectBtn.left;

}

if((GetStyle()&0x0000000f)==CBS_DROPDOWNLIST)

{

CString sText;

GetWindowText(sText);

if(sText.IsEmpty())

{

dc.FillSolidRect(rect, ::GetSysColor(COLOR_WINDOW));

}

else

{

// draw border around edit control

dc.Draw3dRect(rect,

::GetSysColor(COLOR_BTNHIGHLIGHT),

::GetSysColor(COLOR_BTNHIGHLIGHT));

}

Removing the Button of a CComboBox

2008-12-18T16:16:00.000+06:00

int CMyComboBox::OnCreate(LPCREATESTRUCT lpCreateStruct)

{

int nRet = rtn = CComboBox::OnCreate(lpCreateStruct);

COMBOBOXINFO pcb;

pcb.cbSize = sizeof(COMBOBOXINFO);

if(GetComboBoxInfo(&pcb))

{

CEdit* pEdit = (CEdit*)FromHandle(pcb.hwndItem);

if(pEdit != NULL)

{

m_rcComboEdit = pcb.rcItem;

m_rcComboEditUnionBtn.UnionRect(ceRect,&pcb.rcButton);

}

return nRet;

}

void CMyComboBox::HideButton(BOOL bHide)

{

COMBOBOXINFO pcb;

pcb.cbSize = sizeof(COMBOBOXINFO);

if(GetComboBoxInfo(&pcb))

{

CEdit* pEdit = (CEdit*)FromHandle(pcb.hwndItem);

if(pEdit != NULL)

{

if(bHide)

{

pEdit->MoveWindow(m_rcComboEdit.left,

m_rcComboEdit.top,

m_rcComboEditUnionBtn.Width(),

m_rcComboEdit.Height());

}

else

{

pEdit->MoveWindow(m_rcComboEdit.left,

m_rcComboEdit.top,

m_rcComboEdit.Width(),

m_rcComboEdit.Height());

}

RedrawWindow();

}

Modify the width and height of the drop down list in a combo box

2008-12-18T16:14:00.000+06:00

In MFC, you can simply subclass the combo-box and override the WM_CTLCOLOR message handler. This handler is used because Windows sends a message to set the colors for each of the children of the combo (the edit and the list-box), and you can easily grab the list-box HWND at this time.

HBRUSH CMyComboBox::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)

{

if (nCtlColor == CTLCOLOR_LISTBOX)

{

HWND hwndList = pWnd->GetSafeHwnd() ;

if ( hwndList != NULL )

{

CRect rectList ;

::GetWindowRect( hwndList, rectList ) ;

::MoveWindow( hwndList, rectList.left, rectList.top,

(rectList.right - rectList.left + EXTRA_WIDTH),

rectList.bottom - rectList.top + EXTRA_HEIGHT, TRUE ) ;

}

return CComboBox::OnCtlColor( pDC, pWnd, nCtlColor ) ;

}

Resize a combo box at run-time

2008-12-18T16:11:00.000+06:00

/*--------------------------------------------------------------------------------

* Purpose : Set the proper number of lines in a drop-down list or combo box.

* Description : Resizes the combo box window to fit the proper number of lines.

*-------------------------------------------------------------------------------*/

void Set_DropDownSize(CComboBox& box, UINT nLinesToDisplay)

{

CRect cbSize;

box.GetClientRect(cbSize);

int nHeight;

nHeight = box.GetItemHeight(-1); // start with size of the edit-box portion

nHeight += box.GetItemHeight(0) * nLinesToDisplay; // add height of lines of text

// Add the height of the border of the edit box

nHeight += GetSystemMetrics(SM_CYEDGE) * 2; // top & bottom edges

// Add the height of the border of the drop-down box

nHeight += GetSystemMetrics(SM_CYEDGE) * 2; // top & bottom edges

// Set the size of the window

box.SetWindowPos(NULL, 0, 0,

cbSize.right, nHeight, // existing width, new height

SWP_NOMOVE | SWP_NOZORDER // don't move box or change z-ordering.

);

}

How to add MFC support to a simple ATL project

2008-12-01T16:21:00.006+06:00

Step 1:

Add the following:

#define _ATL_CSTRING_EXPLICIT_CONSTRUCTORS

#include afxwin.h

#ifndef _AFX_NO_OLE_SUPPORT

#include afxdisp.h // MFC Automation classes

#endif // _AFX_NO_OLE_SUPPORT

This block should be added before #define _ATL_ALL_WARNINGS

Step 2:

In Configuration properties -> General -> Projects Defaults -> Use of MFC, Select "Use MFC in a Shared DLL"

Step 3:

In the Configuration properties -> C/C++ ->Preprocessor Options section of the Compiler Settings if you are using _USRDLL and _AFXDLL together, try to remove _USRDLL and rebuild again.

We can just add ATL dialog in our project. But there will be some problems such as we can't add Control variables.

Get the Application Directory

2008-12-01T16:20:00.000+06:00

// With standard string

char szAppPath[MAX_PATH] = "";

char szAppDirectory[MAX_PATH] = "";

::GetModuleFileName(0, szAppPath, sizeof(szAppPath) - 1);

// Extract directory

strncpy(szAppDirectory, szAppPath, strrchr(szAppPath, '\\') - szAppPath);

szAppDirectory[strlen(szAppDirectory)] = '\0';

How to open a view in maximized mode

2008-12-01T16:19:00.001+06:00

void CTabbedViewPrjView::OnInitialUpdate()

{

CView::OnInitialUpdate();

GetParentFrame()->ShowWindow(SW_MAXIMIZE);

}

Searching files or folder in a Directory

2008-12-01T16:16:00.000+06:00

CFileFind finder;

BOOL bWorking = finder.FindFile(SearchPath); // SearchPath : "C:\MyFolder\*.*"

while(bWorking)

{

bWorking = finder.FindNextFile();

if(finder.IsDots()) continue;

if(finder.IsDirectory())

{

.....

}

4 Steps to Recreate a Control (when there is no other workaround)

2008-12-01T16:15:00.000+06:00

To recreate a Control you must:

1. Store rectangle and previous window in Z order (to keep Tab work normally).

2. Destroy Control by DestroyWindow().

3. Create Control by CreateWindow(). // put here your styles.

4. Move window to proper Z order by -

SetWindowPos (&wndPrev, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZCTIVATE);

DestroyWindow must be called for tooltips in the OnDestroy Message Handler of the Dialog

2008-12-01T16:13:00.000+06:00

It seems, there is an internal Windows Mechanizm which turns off the WS_CHILDWINDOW style even if it is set for the tooltip control (Traced by SPY). Therefore it is evident, like Jacques said, the tooltip control is not treated like a normal child window of a dialog and it doesn't get destroyed when the Dialog is destroyed.

Therefore, DestroyWindow must be called for tooltips in the OnDestroy Message Handler of the Dialog.

Handle minimize maximize event

2008-12-01T16:12:00.000+06:00

Handle the WM_SYSCOMMAND message. The buttons and menu items on the title bar
are all "system commands" and will generate this message. You'll need to mask
the ID with 0xFFF0 to remove the lowest 4 bits before determining which command
was sent.

Example code:

void CMainFrame::OnSysCommand( UINT nID, LPARAM lParam )

{

UINT nCmd = (nID & 0xFFF0) ;

switch ( nCmd )

{

case SC_SIZE:

// Do something here when user chooses Size command

break ;

case SC_MOVE:

// Do something here when user chooses Move command

break ;

case SC_CLOSE:

// Do something here when user chooses Close or presses X button

break ;

case SC_MAXIMIZE:

// Do something here when user chooses Maximize or presses Maximize button

break ;

case SC_MINIMIZE:

// Do something here when user chooses Minimize or presses Minimize button

break ;

case SC_RESTORE:

// Do something here when user chooses Restore or presses Restore button

break ;

default:

;

}

CFrameWnd::OnSysCommand( nID, lParam ) ;

}

Some Interesting Cursors defined in afxres.h

2008-12-01T14:31:00.001+06:00

// Standard cursors (0x7901->)

// AFX_IDC = Cursor resources

#define AFX_IDC_CONTEXTHELP 30977 // context sensitive help

#define AFX_IDC_MAGNIFY 30978 // print preview zoom

#define AFX_IDC_SMALLARROWS 30979 // splitter

#define AFX_IDC_HSPLITBAR 30980 // splitter

#define AFX_IDC_VSPLITBAR 30981 // splitter

#define AFX_IDC_NODROPCRSR 30982 // No Drop Cursor

#define AFX_IDC_TRACKNWSE 30983 // tracker

#define AFX_IDC_TRACKNESW 30984 // tracker

#define AFX_IDC_TRACKNS 30985 // tracker

#define AFX_IDC_TRACKWE 30986 // tracker

#define AFX_IDC_TRACK4WAY 30987 // tracker

#define AFX_IDC_MOVE4WAY 30988 // resize bar (server only)

// Wheel mouse cursors

// NOTE: values must be in this order! See CScrollView::OnTimer()

#define AFX_IDC_MOUSE_PAN_NW 30998 // pan east

#define AFX_IDC_MOUSE_PAN_N 30999 // pan northeast

#define AFX_IDC_MOUSE_PAN_NE 31000 // pan north

#define AFX_IDC_MOUSE_PAN_W 31001 // pan northwest

#define AFX_IDC_MOUSE_PAN_HV 31002 // pan both axis

#define AFX_IDC_MOUSE_PAN_E 31003 // pan west

#define AFX_IDC_MOUSE_PAN_SW 31004 // pan south-west

#define AFX_IDC_MOUSE_PAN_S 31005 // pan south

#define AFX_IDC_MOUSE_PAN_SE 31006 // pan south-east

#define AFX_IDC_MOUSE_PAN_HORZ 31007 // pan X-axis

#define AFX_IDC_MOUSE_PAN_VERT 31008 // pan Y-axis

A good technique to prevent unnecessary NULL Checking in virtual methods of an inherited class

2008-12-01T14:28:00.002+06:00

Suppose you have a method submit in a class called BOOL CommandProcessor::Submit (CCommand* pCommand), which calls a method virtual BOOL CommandProcessor::DoCommand (CEMCCommand* cmd). The code in the Submit Method goes like this:

BOOL CCmdProcessor::Submit(CCommand* pCommand)

{

if (pCommand != NULL)

{

if(DoCommand(pCommand))

{

.....

}

.....

}

Now somebody when overriding the DoCommand method in his inherited class might write a code such as this

virtual CInheritedCmdProcessor::DoCommand(CCommand* pCommand)

{

if(pCommand != NULL) // -> line X

{

pCommand->Execute();

}

As you can see, the NULL checking in line X is totally unnecessary since we are already checking for NULL in the parent class's CCmdProcessor::Submit method.

But the developer cannot be blamed, since he is receiving a pointer, his first intention would be Safety Checking. Therefore, you can just modify your architecture a little to make sure, unnecessary checking is reduced. Just simply pass a reference instead of a pointer in the DoCommand. Therefore, the developer who is inheriting your class is certain that a valid object is coming and no need to check for NULL memory. Therefore your DoCommand method should be as follows:

virtual CCmdProcessor::DoCommand(CCommand& cmd) and the code in the Submit method should be like this:

BOOL CCmdProcessor::Submit(CCommand* pCommand)

{

if(pCommand != NULL)

{

if(DoCommand(*pCommand))

{

.....

}

.....

}

“errno” is never reset

2008-12-01T14:28:00.001+06:00

The external int variable errno contains the number of the most recent error or warning condition detected by the run-time library. To use this value, include the header file .

If no error or warning condition is detected, the value of errno is 0. After program execution starts, errno is never reset to 0 by the library. Programs that use errno for information about unusual conditions must set it to 0 before calling a library routine that may detect such a condition.

Inheritance problem

2008-12-01T14:27:00.001+06:00

When you made a class child who is inherit from class parent and if parent class has some forward declaration then you received a “Compiler Error C2512 - missing type specifier”.

The solution is removing the forward declaration from the parent class header.

How to convert a pointer to a two dimensional array

2008-12-01T10:58:00.002+06:00

void PassAs2DArray(int a[][10])

{

}

typedef int (*Ptr2Dim) [10];

void main()

{

int* n = (int*)new int [1023];

//PassAs2DArray((int(*)[10])n); -> This also works

PassAS2DArray((Ptr2Dim)n);

}

Method that returns the size of any array declared in stack

2008-12-01T10:58:00.001+06:00

template<typename T, size_t N>

size_t mysizeof(T(&)[N])

{

return N;

}

On this note, here is a way to pass an array by C++ reference style where A has no l-value

void PassArrayByRef(int(&A)[10])

{

// A++; // Illegal

}

The usual way to pass an array where “A” is a pointer

void PassArrayByPtr(int A[10])

{

A++;

}

Select Full Text without changing the Caret pos in CRichEditCtrl

2008-12-01T10:23:00.000+06:00

CPoint pt = GetCaretPos();

int x = CharFromPos(pt);

SetSel(0, -1);

SendMessage(WM_HSCROLL, MAKEWPARAM(SB_THUMBPOSITION, x), 0);

Create DIB section from a BMP file

2008-09-22T15:50:00.007+06:00

// Creates a DIB section from a BMP file

// lpszFileName : Name of the BMP file

// ppvBits : Receive address of bitmap bits

// hSection : Optional handle to a file mapping object

// dwOffset : Offset to the bitmap bit values within hSection

HBITMAP LoadDIBSectionFromFile( LPCTSTR lpszFileName, LPVOID *ppvBits /*= NULL*/, HANDLE hSection /*= NULL*/, DWORD dwOffset /*= 0*/)

{

LPVOID lpBits;

CFile file;

if( !file.Open( lpszFileName, CFile::modeRead) )

return NULL;

BITMAPFILEHEADER bmfHeader;

long nFileLen;

nFileLen = file.GetLength();

// Read file header

if (file.Read((LPSTR)&bmfHeader, sizeof(bmfHeader)) != sizeof(bmfHeader))

{

return NULL;

}

// File type should be ‘BM’

int ch1 = ‘M’;

int ch2 = 8;

int leftshift = ch1 <<>

int ch = ‘B’;

if ( bmfHeader.bfType != (WORD) (leftshift | ch )

{

return NULL;

}

BITMAPINFO *pbmInfo;

pbmInfo = (BITMAPINFO *)::GlobalAlloc(GMEM_FIXED, sizeof(BITMAPINFO) + sizeof(RGBQUAD)*256 );

if (pbmInfo == NULL)

{

return NULL;

}

// Read the BITMAPINFO

file.Read( pbmInfo, sizeof(BITMAPINFO) + sizeof(RGBQUAD)*256 );

BITMAPINFO &bmInfo = *pbmInfo ;

HBITMAP hBmp = CreateDIBSection( NULL, pbmInfo, DIB_RGB_COLORS, &lpBits, hSection, dwOffset );

LPBYTE lpDIBBits; // Pointer to DIB bits

int nColors = bmInfo.bmiHeader.biClrUsed ? bmInfo.bmiHeader.biClrUsed : 1 <<>

if( bmInfo.bmiHeader.biBitCount > 8 )

{

lpDIBBits = (LPBYTE)((LPDWORD)(bmInfo.bmiColors + bmInfo.bmiHeader.biClrUsed) + ((bmInfo.bmiHeader.biCompression == BI_BITFIELDS) ? 3 : 0));

}

else

{

lpDIBBits = (LPBYTE)(bmInfo.bmiColors + nColors);

}

int nOffset = sizeof(BITMAPFILEHEADER) + (lpDIBBits - (LPBYTE)pbmInfo);

file.Seek( nOffset, CFile::begin);

file.ReadHuge((LPSTR)lpBits, nFileLen - nOffset); //bmInfo.biSizeImage );

::GlobalFree(pbmInfo);

if( ppvBits )

{

*ppvBits = lpBits;

}

return hBmp;

}

Converting double to a CString (0.005 to 5e-003)

2008-09-22T15:47:00.001+06:00

Input:

double d = 0.005;

CString strTemp;

strTemp.Format("%.0e",d);

Output : “5e-003”

But if I want “5e-03” then

Input:

// Enable two-digit exponent format

unsigned int old_exponent_format;

old_exponent_format = _set_output_format(_TWO_DIGIT_EXPONENT);

double d = 0.005;

CString strTemp;

strTemp.Format("%.0e",d);

Output : “5e-03”

Conversion to scientific notation is done automatically. But as far as I know “5e-3” is impossible.

Retrieve the Application Directory

2008-09-22T15:46:00.000+06:00

// With standard string

char szAppPath[MAX_PATH] = "";

char szAppDirectory[MAX_PATH] = "";

::GetModuleFileName(0, szAppPath, sizeof(szAppPath) - 1);

// Extract directory

strncpy(szAppDirectory, szAppPath, strrchr(szAppPath, '\\') - szAppPath);

szAppDirectory[strlen(szAppDirectory)] = '\0';

Draw Multi-line Text into a Window in MFC

2008-09-11T16:41:00.001+06:00

// Draw multiline text into a window

// pDC : Specifies the device context

// str : Specifies the string

// rectText : Specifies the text rectangle

// nFirstVisibleLineIndex : Specifies the first visible line index

// nFormat : Specifies the method of formatting the text

void CEMCHotCtrl::DrawMultilineText(CDC* pDC, CString str, CRect rectText, int nFirstVisibleLineIndex, int nFormat)

{

if(str.GetLength() > 0)

{

const TCHAR* p = (LPCTSTR) str;

CSize sz = pDC->GetTextExtent(p);

const TCHAR* end = p;

int nLine = 0;

if(nFirstVisibleLineIndex > 0)

{

while(*end != 0)

{

if(*end == _T('\n'))

{

nLine++;

if(nLine == nFirstVisibleLineIndex)

{

end++;

break;

}

end++;

}

int len = 0;

TCHAR buf[10000];

while(*end != 0)

{

buf[len] = *end;

end++;

len++;

if(*end == _T('\n') || (*end == 0))

{

if(buf[len - 1] == _T('\r'))

{

buf[len - 1] = 0;

}

buf[len] = 0;

pDC->DrawText(buf, -1, rectText, nFormat);

if(*end == _T('\n'))

{

end++;

}

rectText.top += sz.cy;

len = 0;

}

Draw a Transparent Bitmap into the destination DC with Pallete in MFC

2008-09-11T16:27:00.000+06:00

// Draw a transparent bitmap into the destination DC with Pallete

void CEMCHotCtrl::TransparentBlt(HDC hdcDest, int nXDest, int nYDest, int nWidth, int nHeight, HBITMAP hBitmap, int nXSrc, int nYSrc, COLORREF colorTransparent, HPALETTE hPal)

{

CDC dc, memDC, maskDC, tempDC;

dc.Attach( hdcDest );

maskDC.CreateCompatibleDC(&dc);

CBitmap maskBitmap;

// These store return of SelectObject() calls

CBitmap* pOldMemBmp = NULL;

CBitmap* pOldMaskBmp = NULL;

HBITMAP hOldTempBmp = NULL;

memDC.CreateCompatibleDC (&dc);

tempDC.CreateCompatibleDC (&dc);

CBitmap bmpImage;

bmpImage.CreateCompatibleBitmap (&dc, nWidth, nHeight);

pOldMemBmp = memDC.SelectObject (&bmpImage);

// Select and realize the palette

if (dc.GetDeviceCaps (RASTERCAPS) & RC_PALETTE && hPal)

{

::SelectPalette( dc, hPal, FALSE );

dc.RealizePalette();

::SelectPalette( memDC, hPal, FALSE );

}

hOldTempBmp = (HBITMAP) ::SelectObject (tempDC.m_hDC, hBitmap);

memDC.BitBlt (0, 0, nWidth, nHeight, &tempDC, nXSrc, nYSrc, SRCCOPY);

// Create monochrome bitmap for the mask

maskBitmap.CreateBitmap (nWidth, nHeight, 1, 1, NULL);

pOldMaskBmp = maskDC.SelectObject (&maskBitmap);

memDC.SetBkColor (colorTransparent);

// Create the mask from the memory DC

maskDC.BitBlt (0, 0, nWidth, nHeight, &memDC, 0, 0, SRCCOPY);

// Set the background in memDC to black. Using SRCPAINT with black and any other color results in the other color, thus making black the transparent color

memDC.SetBkColor (RGB (0,0,0));

memDC.SetTextColor (RGB (255,255,255));

memDC.BitBlt (0, 0, nWidth, nHeight, &maskDC, 0, 0, SRCAND);

// Set the foreground to black. See comment above.

dc.SetBkColor (RGB (255,255,255));

dc.SetTextColor (RGB (0,0,0));

dc.BitBlt (nXDest, nYDest, nWidth, nHeight, &maskDC, 0, 0, SRCAND);

// Combine the foreground with the background

dc.BitBlt (nXDest, nYDest, nWidth, nHeight, &memDC, 0, 0, SRCPAINT);

if (hOldTempBmp)

::SelectObject (tempDC.m_hDC, hOldTempBmp);

if (pOldMaskBmp)

maskDC.SelectObject (pOldMaskBmp);

if (pOldMemBmp)

memDC.SelectObject (pOldMemBmp);

dc.Detach();

}

Draw a Transparent Bitmap into the destination DC in MFC

2008-09-11T16:24:00.001+06:00

// Draw a transparent bitmap into the destination DC.

void CEMCHotCtrl::TransparentBlt(HDC hdcDest, int nXDest, int nYDest, int nWidth, int nHeight, HBITMAP hBitmap, int nXSrc, int nYSrc, COLORREF cTransparentColor)

{

COLORREF cColor;

HBITMAP bmAndBack, bmAndObject, bmAndMem, bmSave;

HBITMAP bmBackOld, bmObjectOld, bmMemOld, bmSaveOld;

HDC hdcMem, hdcBack, hdcObject, hdcTemp, hdcSave;

POINT ptSize;

hdcTemp = CreateCompatibleDC(hdcDest);

SelectObject(hdcTemp, hBitmap); // Select the bitmap

ptSize.x = nWidth;

ptSize.y = nHeight;

DPtoLP(hdcTemp, &ptSize, 1); // Convert from device

// Create some DCs to hold temporary data.

hdcBack = CreateCompatibleDC(hdcDest);

hdcObject = CreateCompatibleDC(hdcDest);

hdcMem = CreateCompatibleDC(hdcDest);

hdcSave = CreateCompatibleDC(hdcDest);

// Create a bitmap for each DC. DCs are required for a number of GDI functions.

// Monochrome DC

bmAndBack = CreateBitmap(ptSize.x, ptSize.y, 1, 1, NULL);

// Monochrome DC

bmAndObject = CreateBitmap(ptSize.x, ptSize.y, 1, 1, NULL);

bmAndMem = CreateCompatibleBitmap(hdcDest, ptSize.x, ptSize.y);

bmSave = CreateCompatibleBitmap(hdcDest, ptSize.x, ptSize.y);

// Each DC must select a bitmap object to store pixel data.

bmBackOld = (HBITMAP)SelectObject(hdcBack, bmAndBack);

bmObjectOld = (HBITMAP)SelectObject(hdcObject, bmAndObject);

bmMemOld = (HBITMAP)SelectObject(hdcMem, bmAndMem);

bmSaveOld = (HBITMAP)SelectObject(hdcSave, bmSave);

// Set proper mapping mode.

SetMapMode(hdcTemp, GetMapMode(hdcDest));

// Save the bitmap sent here, because it will be overwritten.

BitBlt(hdcSave, 0, 0, ptSize.x, ptSize.y, hdcTemp, 0, 0, SRCCOPY);

// Set the background color of the source DC to the color.

// contained in the parts of the bitmap that should be transparent

cColor = SetBkColor(hdcTemp, cTransparentColor);

// Create the object mask for the bitmap by performing a BitBlt

// from the source bitmap to a monochrome bitmap.

BitBlt(hdcObject, 0, 0, ptSize.x, ptSize.y, hdcTemp, 0, 0, SRCCOPY);

// Set the background color of the source DC back to the original color.

SetBkColor(hdcTemp, cColor);

// Create the inverse of the object mask.

BitBlt(hdcBack, 0, 0, ptSize.x, ptSize.y, hdcObject, 0, 0, NOTSRCCOPY);

// Copy the background of the main DC to the destination.

BitBlt(hdcMem, nXDest, nYDest, ptSize.x, ptSize.y, hdcDest, nXSrc, nYSrc, SRCCOPY);

// Mask out the places where the bitmap will be placed.

BitBlt(hdcMem, 0, 0, ptSize.x, ptSize.y, hdcObject, 0, 0, SRCAND);

// Mask out the transparent colored pixels on the bitmap.

BitBlt(hdcTemp, 0, 0, ptSize.x, ptSize.y, hdcBack, 0, 0, SRCAND);

// XOR the bitmap with the background on the destination DC.

BitBlt(hdcMem, 0, 0, ptSize.x, ptSize.y, hdcTemp, 0, 0, SRCPAINT);

// Copy the destination to the screen.

BitBlt(hdcDest, nXDest, nYDest, ptSize.x, ptSize.y, hdcMem, nXSrc, nYSrc, SRCCOPY);

// Delete the memory bitmaps.

DeleteObject(SelectObject(hdcBack, bmBackOld));

DeleteObject(SelectObject(hdcObject, bmObjectOld));

DeleteObject(SelectObject(hdcMem, bmMemOld));

DeleteObject(SelectObject(hdcSave, bmSaveOld));

// Delete the memory DCs.

DeleteDC(hdcMem);

DeleteDC(hdcBack);

DeleteDC(hdcObject);

DeleteDC(hdcSave);

DeleteDC(hdcTemp);

}

Draw a Disabled Bitmap into the destination DC in MFC

2008-09-09T16:52:00.001+06:00

void CEMCHotButton::DisabledBlt (HDC hdcDest, int nXDest, int nYDest, int nWidth, int nHeight, HBITMAP hBitmap, int nXSrc, int nYSrc)

{

ASSERT (hdcDest && hBitmap);

ASSERT (nWidth > 0 && nHeight > 0);

// Create a generic DC for all BitBlts

HDC hDC = CreateCompatibleDC (hdcDest);

ASSERT (hDC);

if (hDC)

{

// Create a DC for the monochrome DIB section

HDC bwDC = CreateCompatibleDC(hDC);

ASSERT (bwDC);

if (bwDC)

{

// Create the monochrome DIB section with a black and white palette

struct

{

BITMAPINFOHEADER bmiHeader;

RGBQUAD bmiColors[2];

} RGBBWBITMAPINFO =

{

{ // a BITMAPINFOHEADER

sizeof(BITMAPINFOHEADER), // biSize

nWidth, // biWidth;

nHeight, // biHeight;

1, // biPlanes;

1, // biBitCount

BI_RGB, // biCompression;

0, // biSizeImage;

0, // biXPelsPerMeter;

0, // biYPelsPerMeter;

0, // biClrUsed;

0 // biClrImportant;

{

{ 0x00, 0x00, 0x00, 0x00 },

{ 0xFF, 0xFF, 0xFF, 0x00 }

}

};

void* pbitsBW;

HBITMAP hBitmapBW = CreateDIBSection (bwDC, (LPBITMAPINFO) &RGBBWBITMAPINFO, DIB_RGB_COLORS, &pbitsBW, NULL, 0);

ASSERT (hBitmapBW);

if (hBitmapBW)

{

// Attach the monochrome DIB section and the bitmap to the DCs

SelectObject (bwDC, hBitmapBW);

SelectObject (hDC, hBitmap);

// BitBlt the bitmap into the monochrome DIB section

BitBlt (bwDC, 0, 0, nWidth, nHeight, hDC, nXSrc, nYSrc, SRCCOPY);

// Paint the destination rectangle in gray

FillRect (hdcDest, CRect (nXDest, nYDest, nXDest + nWidth, nYDest + nHeight), GetSysColorBrush (COLOR_3DFACE));

// BitBlt the black bits in the monochrome bitmap into COLOR_3DHILIGHT bits in the destination DC

// The magic ROP comes from the Charles Petzold's book

HBRUSH hb = CreateSolidBrush (GetSysColor (COLOR_3DHILIGHT));

HBRUSH oldBrush = (HBRUSH) SelectObject (hdcDest, hb);

BitBlt (hdcDest, nXDest + 1, nYDest + 1, nWidth, nHeight, bwDC, 0, 0, 0xB8074A);

// BitBlt the black bits in the monochrome bitmap into COLOR_3DSHADOW bits in the destination DC

hb = CreateSolidBrush (GetSysColor (COLOR_3DSHADOW));

DeleteObject (SelectObject(hdcDest, hb));

BitBlt (hdcDest, nXDest, nYDest, nWidth, nHeight, bwDC, 0, 0, 0xB8074A);

DeleteObject (SelectObject (hdcDest, oldBrush));

DeleteObject (hBitmapBW);

}

VERIFY (DeleteDC (bwDC));

}

VERIFY (DeleteDC(hDC));

}

Draw a Gradient Rectangle in MFC

2008-09-09T16:48:00.001+06:00

void CEMCHotButton::DrawGradientRect (CDC *pDC, CRect r, COLORREF cLeft, COLORREF cRight, BOOL bVertical)

{

CRect stepR; // rectangle for color's band

COLORREF color; // color for the bands

float fStep;

if(bVertical)

fStep = ((float)r.Height())/255.0f;

else

fStep = ((float)r.Width())/255.0f; // width of color's band

for (int iOnBand = 0; iOnBand <>

{

// set current band

if(bVertical)

{

SetRect(&stepR,

r.left,

r.top+(int)(iOnBand * fStep),

r.right,

r.top+(int)((iOnBand+1)* fStep));

}

else

{

SetRect(&stepR,

r.left+(int)(iOnBand * fStep),

r.top,

r.left+(int)((iOnBand+1)* fStep),

r.bottom);

}

// set current color

color = RGB((GetRValue(cRight)-GetRValue(cLeft))*((float)iOnBand)/255.0f+GetRValue(cLeft),

(GetGValue(cRight)-GetGValue(cLeft))*((float)iOnBand)/255.0f+GetGValue(cLeft),

(GetBValue(cRight)-GetBValue(cLeft))*((float)iOnBand)/255.0f+GetBValue(cLeft));

// fill current band

pDC->FillSolidRect(stepR,color);

}

Convert an Icon to a Bitmap image in MFC

2008-09-09T16:43:00.002+06:00

HBITMAP CHotButton::ConvertIconToBitmap(HICON hIcon)

{

CClientDC clientDC(this);

CDC dc;

dc.CreateCompatibleDC(&clientDC);

CRect rectButton;

GetClientRect (&rectButton);

CSize sizeButton = rectButton.Size();

// bitmap size:

int cx = 0, cy = 0;

if (sizeButton.cy <=16)

{

// bitmap size:

cx = 12;

cy = 12;

}

else if (sizeButton.cy > 16)

{

// bitmap size:

cx = 16;

cy = 16;

}

CBitmap bmp;

bmp.CreateCompatibleBitmap(&clientDC, cx, cy);

CBitmap* pOldBmp = (CBitmap*)dc.SelectObject(&bmp);

::DrawIconEx( dc.GetSafeHdc(), 0, 0, hIcon, cx, cy, 0, (HBRUSH)RGB(192, 192, 192), DI_NORMAL);

dc.SelectObject( pOldBmp );

dc.DeleteDC();

// return the image

return ((HBITMAP)::CopyImage((HANDLE)((HBITMAP)bmp), IMAGE_BITMAP, 0, 0, LR_DEFAULTSIZE | LR_CREATEDIBSECTION));

}

Loading a bitmaps from a MFC DLL resource

2008-09-08T17:45:00.000+06:00

HMODULE hPrevInst = AfxGetResourceHandle();

HMODULE hDLLInstance = ::LoadLibrary( _T("ESIMFCControls"));

if (hDLLInstance != NULL)

{

AfxSetResourceHandle(hDLLInstance);

CBitmap bmp;

if ( bmp.LoadBitmap(MAKEINTRESOURCE(IDB_FILTER_BITMAP)) )

{

CDC dcMemory;

BITMAP bm;

dcMemory.CreateCompatibleDC(pDC);

dcMemory.SelectObject(&bmp);

// Get the height and width of the bitmap

bmp.GetBitmap(&bm);

pDC->BitBlt(rcFilter.left, rcFilter.top, bm.bmWidth, bm.bmHeight, &dcMemory, 0, 0, SRCCOPY);

}

// Restore previous resource handle

AfxSetResourceHandle(hPrevInst);

}

Delete All Elements from a Singly Linked List

2008-08-29T21:07:00.002+06:00

When we want to remove all the elements from a linked list, the natural inclination is to use a single pointer to traverse the list, freeing elements as we go. A problem arises, however, when this is implemented. Do we advance the pointer or free the element first? If we advance the pointer first, then the freeing is impossible because we overwrote the pointer to the element to be freed. If we free the element first, advancing the pointer is impossible because it involves reading the next pointer in the element that was just freed. The solution is to use two pointers.

Example Code:

void DeleteAllElement( ListElement **head )

{

ListElement *deleteMe = *head;

while( deleteMe )

{

ListElement *next = deleteMe->next;

delete deleteMe;

deleteMe = next;

}

*head = NULL;

}

Delete an item from a Singly Linked List

2008-08-29T21:07:00.001+06:00

Because elements in a singly-linked list are maintained exclusively with links to the next element, any insertion or deletion of elements in the middle of a list requires modification of the previous element’s link. This may require a traversal of the list, because there’s no other way to find a preceding element. Special care must be taken when dealing with the head of the list.

Example Code:

bool DeleteElement( ListElement **head, ListElement *deleteMe )

{

ListElement *elem = *head;

// special case for head

if( deleteMe == *head )

{

*head = elem->next;

delete deleteMe;

return true;

}

while( elem )

{

if( elem->next == deleteMe )

{

/* elem is element preceding deleteMe */

elem->next = deleteMe->next;

delete deleteMe;

return true;

}

elem = elem->next;

}

// not found

return false;

}

Finding an item from a Singly Linked List

2008-08-29T21:06:00.002+06:00

Operations on any but the first element of a linked list require traversal of some elements of the list, and you must always check for the end of the list.

ListElement Find( ListElement head, int data )

{

while( head != NULL && head.data != data )

{

head = head.next;

}

return head;

}

Tracking the Head Element of a Singly Linked List

2008-08-29T21:06:00.001+06:00

The head element of a singly-linked list must always be tracked; otherwise, the list will be lost in memory. This means that the pointer or reference to the head of the list must be updated when a new element is inserted ahead of the first element or when the existing first element is removed from the list. Tracking the head element becomes a problem when you alter the list inside a function or method, because the caller must be made aware of the new head element.

Example Code:

bool InsertInFront( ListElement **head, int data )

{

ListElement *newElem = new ListElement;

if( !newElem ) return false;

newElen->data = data;

*head = newElem;

return true;

}

Linked List

2008-08-29T20:57:00.004+06:00

There are three basic kinds of linked list: singly-linked lists, doubly-linked lists and circularly-linked lists. The singly-linked lists is in first figure and doubly-linked lists is in second figure is below.

Declaration:

typedef struct ListElement

{

struct ListElement *next;

int data;

} ListElement;

typedef struct DoublyLinkedList

{

struct DoublyLinkedList *next;

struct DoublyLinkedList *prev;

int data;

} DoublyLinkedList;

How to post self pop-up menu for CHtmlView in MFC

2008-08-21T15:31:00.004+06:00

Just override the CHtmlView::OnShowContextMenu funcion and return S_OK.

HRESULT CWebBrowserView::OnShowContextMenu(DWORD dwID, LPPOINT ppt, LPUNKNOWN pcmdtReserved, LPDISPATCH pdispReserved)

{

CMenu menu;

int pMenuID = 0;

VERIFY(menu.LoadMenu(IDR_WEBBROWSER));

CMenu* pPopup = menu.GetSubMenu(pMenuID);

ASSERT(pPopup != NULL);

pPopup->TrackPopupMenu(TPM_LEFTALIGN |TPM_RIGHTBUTTON, ppt->x, ppt->y, this);

return S_OK;

// Don't call the base version

/*return CHtmlView::OnShowContextMenu(DWORD dwID, LPPOINT ppt, LPUNKNOWN pcmdtReserved, LPDISPATCH pdispReserved);*/

}

How to disable the default pop-up menu for CHtmlView in MFC

2008-08-21T15:29:00.002+06:00

Read the article: http://support.microsoft.com/kb/236312

Just override the CHtmlView::OnShowContextMenu funcion and return S_OK.

HRESULT CWebBrowserView::OnShowContextMenu(DWORD dwID, LPPOINT ppt, LPUNKNOWN pcmdtReserved, LPDISPATCH pdispReserved)

{

return S_OK;

// Don't call the base version

/*return CHtmlView::OnShowContextMenu(DWORD dwID, LPPOINT ppt, LPUNKNOWN pcmdtReserved, LPDISPATCH pdispReserved);*/

}

BE CAREFUL!!!

2008-04-15T16:34:00.002+06:00

(01) Always write optimize and good code in WM_PAINT, WM_MOUSEMOVE and WM_CTLCOLOR event handler. In these three event handlers is always called and it’s tough to debug if any bug exists.

(02) When you got the device context by GetDC() api, you must make sure to release the device context by ReleaseDC() api after painting.

DECLARE_DYNCREATE problem

2008-04-10T13:58:00.000+06:00

When you want a class, who will dynamically created by CreateObject(), then you must have a default constructor. Otherwise you got “Compiler Error C2512 - no appropriate default constructor available”.

Forward Declaration problem

2008-04-10T13:55:00.000+06:00

When you made a class child who is inherit from class parent and if parent class has some forward declaration then you received a “Compiler Error C2512 - missing type specifier”.

The solution is remove the forward declaration from the parent class header.

4 Steps to Recreate a Control (when there is no other workaround)

2008-03-11T15:44:00.000+06:00

To recreate a Control you must:

1. Store rectangle and previous window in Z order (to keep Tab work normally)
2. Destroy Control by DestroyWindow;
3.Create Control by CreateWindow(); // put here your styles.
4. move window to proper Z order by:
SetWindowPos(&wndPrev, 0,0,0,0, SWP_NOMOVE_SWP_NOSIZE|SWP_NOZCTIVATE);

The second argument of the DYNAMIC_DOWNCAST macro cannot be const for the IBM platform

2008-03-11T15:39:00.001+06:00

In Windows platform DYNAMIC_DOWNCAST macro can take const or non const pointer as second argument.

But the second argument of DYNAMIC_DOWNCAST macro cannot be const for the IBM platform.

How to become a good programmar

2008-03-11T15:37:00.000+06:00

I’m putting some suggestions here for the fresh graduates and the college freshmen on how to become a good programmer.

In my own definition, a fresh graduate good/skilled programmer should have the followings:

Strong skill of one or more good languages like C++, Java and C#.

Must have strong skills with control structures. Don’t mess up if you’re asked to print out triangle or other shaped piles of ‘x’s with loops.
Must have strong skills with recursion. You must know how to transform a looped task into a recursive one and vice versa, for example: multiplication using addition recursively.
If your language is C++, you must know how to play with pointers and references.
Understand pass by value and reference.
Clearly understand scopes and memory allocation, de-allocation. Know when a object is destroyed and when to destroy.
Know the usage of all operators including bit-wise ones.

In-depth knowledge of OOP.

Only being able to write classes and doing encapsulation and inheritance is not what you should call good OOP.
Clearly understand how function overloading, overriding, polymorphism works.
Clearly understand how constructor/destructor (if any) works with inheritance.
Clearly know the difference and use of Interfaces and Abstract classes.
Know how to overload operators. Why and how copy constructor is defined/used.

Know common data structures

At least know the common data structures like stack, queue, linked list, doubly linked list (know circular version of all of them) and trees.
Be a skilled implementer of any of those, have clear concept of push, pop, add, delete, peek etc method works on those data structures.

Know most common algorithms well

You don’t need to memorize pseudo codes line by line but you need to have clear concept of most common algorithms of sorting(bubble, quick, merge, heap, bucket, etc), searching (including DFS, BFS), etc.
As a fresher you must know their time and space complexities, pitfalls and improvements (if any).

General computing concepts:

Know processes and threads, how are they related to each other, how to program them, etc.
Understand TCP/IP: Don’t think it’s only the network administrator’s task to understand TCP/IP. All programmers ever doing any network or web programming should have clear TCP/IP concepts and understanding.

Be skilled in debugging in IDE:

Be skilled in any or many of Visual Studio/Visual Studio.Net, Eclipse, Netbeans, KDevelop, etc.
Know how to debug your code.

Have basic knowledge of Software Engineering and SDLC.

Some advice for college freshmen:

Start with C++ or Java, avoid starting with scripting languages:

If you’re learning programming for the first time, avoid starting with scripting or loosely typed languages like: PHP, ASP, Perl, etc or Visual Basic. It may destroy your understanding of program execution, data types, memory allocation, etc.
Start with C++ or Java. If you want to me to be specific, start with C++, you’ll love it for the rest of your life.. :) It’ll be easier for you to learn (almost) any other language (like: C#, PHP, ASP, etc).
If you ask, do you need to know C to start with C++? Or should you learn C first and then C++? The answer is ‘no’.

If you want to be good programmer, keep on coding at least 20 hours a week for next 4 years :).

Never stop learning new technologies that are coming out everyday.

Know something’s of many things but be master of one. Know at least one language very well.

Replace Color of a bitmap with a new color

2008-03-11T15:36:00.000+06:00

1. Fill the DC with the new color

2. Draw the bitmap transparently into the DC with the Old Color (the color to be replaced) as the mask color

Example Code :

BOOL CMFCBitmap::ReplaceColor(COLORREF crOld, COLORREF crNew)

{

CDC memDC;

CBitmap bmpTrans;

CBitmap *pOldBitmap;

POINT ptSize;

BOOL bResult;

// Create one DC to hold temporary data.

bResult = memDC.Attach(::CreateCompatibleDC(NULL));

if(bResult == FALSE)

return FALSE;

// Compute the bitmap dimension

if(!this->GetBitmapSize(&(ptSize.x), &(ptSize.y)))

return FALSE;

// Convert from device

memDC.DPtoLP(&ptSize, 1);

BITMAP bm;

GetObject(m_hBitmap, sizeof(BITMAP), (LPSTR)&bm);

CMFCBitmap bmp;

if(bmp.CopyBitmap(m_hBitmap, MFCBI_NORMAL) == FALSE)

return FALSE;

// Create the transparent bitmap

bmpTrans.Attach(this->Detach());

Attach(bmp.Detach());

// Select the bitmap

pOldBitmap = (CBitmap*)memDC.SelectObject(&bmpTrans);

CRect rc(0,0, ptSize.x, ptSize.y);

memDC.FillSolidRect(rc, crNew);

DrawTransparent(&memDC, 0,0, crOld);

memDC.SelectObject(pOldBitmap);

// Destroy the previous bitmap

DeleteObject(Detach());

HBITMAP hMaskedBitmap = (HBITMAP)bmpTrans.Detach();

// Attach to the transparent bitmap

if(!Attach(hMaskedBitmap))

{

DeleteObject((HGDIOBJ)hMaskedBitmap);

return FALSE;

}

return TRUE;

}

#DEFINE VS ENUM revisited

2008-03-11T12:54:00.001+06:00

Tried to declare an enum inside a class like CEMCHotButton:

enum TextAlignment

{

TA_LEFT = 0

};

And there were 100 errors showing up without any traceable reason.

Finally I found that, a same DEFINE is declared in WINGDI.H header file and it’s made a conflict with my DEFINE value.

Now the problem is, define cannot be put under a namespace or any scope, therefore I have to change the enum type name.

This is forcing me to name TA_LEFT, to TF_LEFT.

Safe memory deletion

2007-12-31T12:44:00.000+06:00

Always Set NULL when delete a memory. Otherwise the program may crash when the variable further referenced.

Example:

delete m_pComboArgs;

m_pComboArgs = NULL;

CBN_SELCHANGE and CBN_CLOSEUP message handler of CComboBox class made conflict

2007-12-31T11:31:00.000+06:00

The MFC CComboBox is weird. The CBN_SELCHANGE and CBN_CLOSEUP message handler doesn’t call proper sequence. Sometimes the CBN_CLOSEUP call first time and later CBN_SELCHANGE. It’s made confusion. So carefully write code in those two event handler.

Change Default Dialog Font of CDialog

2007-12-31T11:29:00.000+06:00

Sometimes it is desirable to change the default font specified in dialog templates (usually "MS Sans Serif", 8 pts.) at runtime (dynamically). For example, you may want to increase the font size to make it more readable under higher screen resolutions. MFC library contains a class CDialogTemplate, that serves exactly this purpose, but Microsoft has not bothered to include its description in standard MFC reference. This is how you can use this class in your code:

1. Place the following string somewhere in your "StdAfx.h" file:

#include

2. Override DoModal() function in your dialog class:

int CSimpleDialog::DoModal()

{

CDialogTemplate dlt;

int nResult;

// load dialog template

if (!dlt.Load(MAKEINTRESOURCE(CSimpleDialog::IDD))) return -1;

// set your own font, for example "Arial", 10 pts.

dlt.SetFont("Arial", 10);

// get pointer to the modified dialog template

LPSTR pdata = (LPSTR)GlobalLock(dlt.m_hTemplate);

// let MFC know that you are using your own template

m_lpszTemplateName = NULL;

InitModalIndirect(pdata);

// display dialog box

nResult = CDialog::DoModal();

// unlock memory object

GlobalUnlock(dlt.m_hTemplate);

return nResult;

}

Set Default font to any custom made MFC control

2007-12-31T11:14:00.000+06:00

LOGFONT lf;

int nRet = GetObject(GetStockObject(DEFAULT_GUI_FONT), sizeof(LOGFONT), &lf);

if (nRet)

{

// Set the Default font to the Custom window control

m_hotListCtrl.SetFont(&lf);

}

Using TrackMouseEvent to find out when the Mouse Leaves from the Window

2007-12-05T13:22:00.000+06:00

Using TrackMouseEvent is pretty simple. When the mouse enters the window you want to track, you call track mouse event telling it to inform you when the mouse leaves. When it does, it will send a WM_MOUSELEAVE message to that window.

Sample code:

// HotEdit.h changes

class CHotEdit : public CEdit
{
protected:
BOOL m_bMouseTracking;
afx_msg LRESULT OnMouseLeave(WPARAM wParam, LPARAM lParam);
...
};

// HotEdit.cpp changes

BEGIN_MESSAGE_MAP(CHotEdit, CEdit)
 ON_MESSAGE(WM_MOUSELEAVE, OnMouseLeave)
END_MESSAGE_MAP()

CHotEdit::CHotEdit()
{
 m_bMouseTracking = FALSE;
}

LRESULT CHotEdit::OnMouseLeave(WPARAM wParam, LPARAM lParam)
{
m_bMouseTracking = FALSE;
 return TRUE;
}

void CHotEdit::OnMouseMove(UINT nFlags, CPoint point)
{
if (!m_bMouseTracking)
{
  TRACKMOUSEEVENT tme;
tme.cbSize = sizeof(TRACKMOUSEEVENT);
tme.dwFlags = TME_LEAVE;
tme.hwndTrack = this->m_hWnd;

  if (::_TrackMouseEvent(&tme))
{
   m_bMouseTracking = TRUE;
}

 }

CEdit::OnMouseMove(nFlags, point);
}

How to subclass CListBox and CEdit inside of CComboBox

2007-12-05T12:37:00.000+06:00

SUMMARY

While it is simple to directly subclass a combo box control, it is not simple to subclass the edit or list box inside a combo box. The problem is that it is difficult to get the HWNDs of the child controls in a portable manner.

One safe way to subclass the internal edit and list box controls is to subclass them in the WM_CTLCOLORXXX messages. Because Win32 sends separate WM_CTLCOLOREDIT and WM_CTLCOLORLISTBOX messages, these messages are safe and easy ways to get the HWNDs of the child controls of the combo box.

Below is a CSuperComboBox class, which is an MFC implementation of this method. Because MFC routes all the WM_CTLCOLOR messages to OnCtlColor, the subclassing takes place there.

MORE INFORMATION

Use ClassWizard to derive a class from CComboBox and add message handlers for WM_CTLCOLOR and WM_DESTROY. Then manually edit the header file to add the data members, m_edit and m_listbox. Finally, copy the code from the message handlers below:

Sample code:

// SuperComboBox.h : header file

class CSuperComboBox : public CComboBox

{

public:

CEdit m_edit;

CListBox m_listbox;

protected:

afx_msg HBRUSH OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor);

afx_msg void OnDestroy();

...

};

// SuperComboBox.cpp : implementation file

HBRUSH CSuperComboBox::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)

{

if (nCtlColor == CTLCOLOR_EDIT)

{

// Edit control

if (m_edit.GetSafeHwnd() == NULL)

m_edit.SubclassWindow(pWnd->GetSafeHwnd());

}

else if (nCtlColor == CTLCOLOR_LISTBOX)

{

//ListBox control

if (m_listbox.GetSafeHwnd() == NULL)

m_listbox.SubclassWindow(pWnd->GetSafeHwnd());

}

HBRUSH hbr = CComboBox::OnCtlColor(pDC, pWnd, nCtlColor);

return hbr;

}

void CSuperComboBox::OnDestroy()

{

if (m_edit.GetSafeHwnd() != NULL)

m_edit.UnsubclassWindow();

if (m_listbox.GetSafeHwnd() != NULL)

m_listbox.UnsubclassWindow();

CComboBox::OnDestroy();

}

Good Code

2007-11-11T15:12:00.000+06:00

01. Never allocate memory like this way

void MyFunc(CString strText)

{

int size = strText.GetLength();

TCHAR* pszNewText = new TCHAR[size];

// Good practice is: TCHAR* pszNewText = new TCHAR[size+1];

}

02. Never just delete memory say delete pMyObj, always set pMyObj = NULL after delete

03. Although it doesn't make much difference, but always use the [] operator after using delete for arrays.

Example:

// Always better to use [] after delete for array of any sort of datatypes

delete[] myarray;

04. Avoid Using In/Out Parameters.

That is Avoid using the same parameter as Input as well as output parameter.

Example:

Bad code:

BOOL GetMergedCellRect(CRect& rect)

{

rect.top++;

rect.bottom--;

Return TRUE;

}

Good Code:

BOOL GetMergedCellRect(CRect rect, /*OUT*/CRect& mergedRect)

{

mergedRect = rect;

mergedRect.top++;

mergedRect.bottom--;

}

Although if u have a method such as InflateRect, DeflateRect, whose names are obviously and clearly stating you to do some operation on the passed rectangle, in those cases you can off course use the same parameter as input and output.

05. I think it would be a good idea to typedef the parent class as Super inside the child class.

Example:

class wxEdit : public wxWindow

{

typedef wxWindow Super;

public:

void OnPaint()

{

Super::OnPaint();

}

This technique is used in Symbian OS.

06. Although we did some ugly hacking because of the circumstances, but the following is not acceptable. You cannot allow your base class to know about your child classes,

For example, you should never declare a child class a friend of your base class unless absolutely necessary.

class CHotListCtrlCellBase : public CObject

{

friend class CHotListCtrlURLCell;

friend class CHotListCtrlCellCombo;

friend class CHotListCtrlCellCheck;

...

};

06. All of us may be confused or do mistake while using memset() function.

Here is an example that shows correct way of using memset():

TCHAR* pBuff = new TCHAR[256];

~~memset( pBuff, 0, 256);~~

memset( pBuff, 0, 256*sizeof(TCHAR));

List of BAD Coding Conventions

2007-11-04T14:55:00.000+06:00

1. Using unnecessary double pointers...

GetNodeName(Node** ppNode)

{

return *ppNode->GetName();

}

U should only use a double pointer when you are allocating your memory with new or malloc() inside a method and passing a pointer as argument to get the newly allocated memory address.

Example:

BOOL COM_CREATE_OBJECT(ComObj** pObj)

{

ComObj* pNewObj = new ComObj;

if(pNewObj)

{

*pObj = pNewObj;

return TRUE;

}

return FALSE;

}

void main()

{

ComObj** pObj = NULL;

// in this case you have to use double pointer.

COM_CREATE_OBJECT(&pObj);

}

2. Converting TCHAR to WCHAR (or WCHAR equivalent), or TCHAR to char (or char equivalent), by simple type casting..

Example:

WCHAR* nodeName = xmlPareser->GetNodeName();

TCHAR* convertedName = (TCHAR*) nodeName;

3. Assuming WCHAR, or wchar_t to be a typedef of unsigned short...

4. Using... wierd macro function names such as Z(), W(), X().. etc..

Example:

WCHAR* fileNameW = GetFileNameW();

TCHAR* fileName = X(fileNameW)... // here x is a function which converts wchar to tchar...

5. Returning temporary pointers as return type

Example:

TCHAR* convertUnicodeToTChar(WCHAR* str)

{

TCHAR buf[255];

wcstombs(buf, str);

// returning temporary pointer ... very dangerous indeed.., maybe u can
// use a global or member variables in this case..

return buf;

}

6. Doing Too Much Processing (such as running a big for loop) in OnMouseMove(), OnEraseBkGnd, OnPaint(), OnCmdUI() etc.

Porting Guidelines

2007-11-04T14:51:00.000+06:00

Be careful with use of lower-case letter and upper-case letter concerning the file names because Unix platforms are case sensitive.

If the name of the file is VSessionManager.h

Bad Code:
#include "vsessionmanger.h"

Good Code:
#include "VSessionManger.h"
Do not use #pragma once. Use #if !defined() #endif

Bad Code:
#pragme once

Goode Code:
#if !defined(__MYHEADER_H__)
#define __MYHEADER_H__
...
#endif
To precise a path for include file, use '/' instead of '\', even on Windows.

Bad Code:
#include "..\CmdInterpreter\CmdInterpreter.h"

Good Code:
#include "../CmdInterpreter/CmdInterpreter.h"
When manipulating string path, do not use '\' as a separator, because the separator can be '/'. You should use the defined variable PATH_SEPARATOR_STR.

Bad Code:
ptr = strrchr(font_path, '\\');

Good Code:
ptr = strrchr(font_path, PATH_SEPARATOR_STR);
Do not declared a variable within a block if you need to use it after this block.

Bad Code:
for( int i = 0; i < nb; i++ ) {…}
...
for( i = 0; i < 10; i++ ) {…}

Good Code:
int i;
for( i = 0; i < nb; i++ ) {…}
...
for( i = 0; i <>
Do not create a function without type.

Bad Code:
toto();

Good Code:
void toto() or int toto();
Do not use the following CString functions:

Append - you have to use the += operator
IsEmpty - you have to do a comparison by using GetSize
LoadString(HINSTANCE hInstance, UINT nID) - you can use only LoadString(UINT nID)

Do not use the following CStringArray functions:

GetCount - you have to use GetSize

Do not use the following CPoint functions:

SetPoint - you should use the x and y members

Do not use the following CSize functions:

SetSize - you should use the cx and cy members

Do not use the following CMap functions:

GetSize - you should use GetCount

Do not use the following CRect functions:

MoveToXY

The code automatically generated by Visual Studio in the Message Map are not correct. You have to remove the "&classname::"

Bad Code:
ON_LBN_SELCHANGE(IDC_LANGUAGE_LIST, &CLanguageSelDlg::OnLButtonDownLanguageList)

Good Code:
ON_LBN_SELCHANGE(IDC_LANGUAGE_LIST, OnLButtonDownLanguageList)
When using DYNAMIC_DOWNCAST we need to make sure we use DECLARE_DYNAMIC and IMPLEMENT_DYNAMIC for the base class and the dereived class. Otherwise, there will be a compile error in unix platforms.
When called a C method from a C++ method, use the extern C convention.

Bad Code:
toto.h: int myfunction();
toto.c: int myfunction() { return 1; }
toto_called.cpp: void myfunction2() { int i = myfunction(); }

Good Code:
toto.h:
#ifdef __cplusplus
extern "C" {
#endif
int myfunction();
#ifdef __cplusplus
}
#endif
toto.c: int myfunction() { return 1; }
toto_called.cpp: void myfunction2() { int i = myfunction(); }

Remove the WS_BORDER style for a CEdit control programmatically?

2007-10-25T16:19:00.000+06:00

void CMyEdit::RemoveBorder()

{

DWORD dwStyle = ::GetWindowLong(m_hWnd, GWL_EXSTYLE);

If (dwStyle & WS_EX_CLIENTEDGE)

{

ModifyStyleEx(WS_EX_CLIENTEDGE,0);

SetWindowPos(NULL, 0, 0, 0, 0, SWP_FRAMECHANGED | SWP_NOSIZE | SWP_NOMOVE | SWP_NOZORDER );

}

Common Class Declaration Mistake

2007-10-25T16:10:00.000+06:00

class CComboCellTypeArgs : public HotListCtrlCellTypeArgs
{
public:
CComboCellTypeArgs(void);
virtual ~CComboCellTypeArgs(void);

public:
CStringArray m_arrString;
}

If u just missed to write a semicolon after class declaration, u will be get some horrible compilation error like the following:

error C2533: 'HotListCtrlCellTypeArgs::{ctor}' : constructors not allowed a return type

So don’t miss to write the semicolon after class declaration!!!

Some Constants doesn’t work at VC++ 6.0.

2007-10-25T16:02:00.000+06:00

Solution:

// For Visual C++ 6.0 Compatible and also Upper Version

#ifndef VK_OEM_MINUS

#define VK_OEM_MINUS 0xBD // '-' any country

#endif

#ifndef VK_OEM_PERIOD

#define VK_OEM_PERIOD 0xBE // '.' any country

#endif

#ifndef IDC_HAND

#define IDC_HAND MAKEINTRESOURCE(32649)

#endif

ON_WM_TIMER() message map probelm at Win64 Build

2007-10-25T15:48:00.000+06:00

At VC++ 6.0 ON_WM_TIMER() Function prototype is

afx_msg void OnTimer (UINT nIDEvent);

Which get a compilation error when u builds it at Windows 64-bit. So use the new function prototype is

afx_msg void OnTimer (UINT_PTR nIDEvent);

Set Default Font to any MFC Control

2007-10-25T02:41:00.000+06:00

// Set the Default font to the Window

::SendMessage(this->m_hWnd, WM_SETFONT, WPARAM(GetStockObject(DEFAULT_GUI_FONT)), LPARAM(TRUE));