To change the background color of an edit control in an MFC
application, you must override the OnCtlColor() message-handling function of
the window containing the edit control.
In the new OnCtlColor()
function, set the background color and return a handle to a brush that will be
used for painting the background. This must be done in response to receiving
both the CTLCOLOR_EDIT and CTLCOLOR_MSGBOX messages in the OnCtlColor()
function.
This is also documented in the "Class Library Reference"
under CWnd::OnCtlColor().
The sample code below uses a CDialog-derived class to
demonstrate the process. Class Wizard was used to generate message-handling
functions for the WM_CTLCOLOR and WM_DESTROY messages. These functions are
called CEditDialog::OnCtlColor() and CEditDialog::OnDestroy(), respectively.
Note In Visual C++ .NET you can add the WM_CTLCOLOR and WM_DESTROY
handlers for the dialog object from the Properties Window. All the available
messages for the dialog are listed in the Messages tab.
Sample code
// editdlg.h : header file
//
////////////////////////////////////////////////////////////////////////
///
// CEditDialog dialog
class CEditDialog : public CDialog
{
// Construction
public:
CEditDialog(CWnd* pParent = NULL); // standard constructor
// Add a CBrush* to store the new background brush for edit controls.
CBrush* m_pEditBkBrush;
// Dialog Data
//{{AFX_DATA(CEditDialog)
enum { IDD = IDD_EDITDIALOG };
// NOTE: The ClassWizard will add data members here.
//}}AFX_DATA
// Overrides
// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(CEditDialog)
protected:
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support
//}}AFX_VIRTUAL
// Implementation
protected:
// Generated message map functions
//{{AFX_MSG(CEditDialog)
afx_msg HBRUSH OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor);
afx_msg void OnDestroy();
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
};
// editdlg.cpp : implementation file
//
#include "stdafx.h"
#include "mdi.h"
#include "editdlg.h"
#ifdef _DEBUG
#undef THIS_FILE
static char BASED_CODE THIS_FILE[] = __FILE__;
#endif
//////////////////////////////////////////////////////////////////////
// CEditDialog dialog
CEditDialog::CEditDialog(CWnd* pParent /*=NULL*/)
: CDialog(CEditDialog::IDD, pParent)
{
//{{AFX_DATA_INIT(CEditDialog)
// NOTE: The ClassWizard will add member initialization here.
//}}AFX_DATA_INIT
// Instantiate and initialize the background brush to black.
m_pEditBkBrush = new CBrush(RGB(0, 0, 0));
}
void CEditDialog::DoDataExchange(CDataExchange* pDX)
{
CDialog::DoDataExchange(pDX);
//{{AFX_DATA_MAP(CEditDialog)
// NOTE: The ClassWizard will add DDX and DDV calls here.
//}}AFX_DATA_MAP
}
BEGIN_MESSAGE_MAP(CEditDialog, CDialog)
//{{AFX_MSG_MAP(CEditDialog)
ON_WM_CTLCOLOR()
ON_WM_DESTROY()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
//////////////////////////////////////////////////////////////////////
// CEditDialog message handlers
HBRUSH CEditDialog::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)
{
switch (nCtlColor) {
case CTLCOLOR_EDIT:
case CTLCOLOR_MSGBOX:
// Set color to green on black and return the background
brush.
pDC->SetTextColor(RGB(0, 255, 0));
pDC->SetBkColor(RGB(0, 0, 0));
return (HBRUSH)(m_pEditBkBrush->GetSafeHandle());
default:
return CDialog::OnCtlColor(pDC, pWnd, nCtlColor);
}
}
void CEditDialog::OnDestroy()
{
CDialog::OnDestroy();
// Free the space allocated for the background brush
delete m_pEditBkBrush;
}
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