Hi,

There is no direct method to set the background color of a dialog box.

However, you can do by the following method,

Create a CBrush member variable for the CDialog derived class
   CBrush m_pbkBrush;

in OnInitDialog create the brush with a suitable color
   m_pbkBrush.CreateSolidBrush(RGB(255,0,0));

add WM_CTLCOLOR message map and make the following changes in the message
handler function

HBRUSH CMFCTabDlg::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)
{
   HBRUSH hbr;
   if (nCtlColor == CTLCOLOR_DLG)
       hbr = (HBRUSH)m_pbkBrush.GetSafeHandle();
   else
       hbr = CDialog::OnCtlColor(pDC, pWnd, nCtlColor);
   return hbr;
}

and whereever you want the background to be changed like your button click,
delete the old brush object and recreate with the new color and call
Invalidate()

m_pbkBrush.DeleteObject();
m_pbkBrush.CreateSolidBrush(RGB(0,255,0));
Invalidate();

------------------------------
Ashok K Kumar