How To Get a Dialog to Use an Icon When Minimized

MORE INFORMATION

The standard dialog box class specifies NULL as the value of the hIcon field of its WNDCLASS structure. So no icon is drawn when the standard dialog box is minimized.

An icon can be specified by getting the dialog to use a private class as follows:

1. Register a private class.

         WNDCLASS wc;
   
         wc.style = CS_DBLCLKS | CS_SAVEBITS | CS_BYTEALIGNWINDOW;
         wc.lpfnWndProc = DefDlgProc;
         wc.cbClsExtra = 0;
         wc.cbWndExtra = DLGWINDOWEXTRA;
         wc.hInstance = hinst;
         wc.hIcon = LoadIcon(hinst, "DialogIcon");
         wc.hCursor = LoadCursor(NULL, IDC_ARROW);
         wc.hbrBackground = COLOR_WINDOW + 1;
         wc.lpszMenuName = NULL;
         wc.lpszClassName = "MyDlgClass";
         RegisterClass(&wc);
   						

   NOTE: The default dialog window procedure, DefDlgProc(), is used as the window procedure of the class. This causes windows of this class to behave as standard dialogs. The cbWndExtra field has to be assigned to DLGWINDOWEXTRA - the dialog box stores its internal state information in these extra window bytes. The icon to be used when the dialog box is minimized is assigned to the hIncon field.
2. Get the dialog box to use the private class. Use the CLASS statement in the dialog box template to get the dialog box to use the private class:

         IDD_MYDIALOG DIALOG 0, 0, 186, 92
         CLASS "MyDlgClass"
         :
   					

3. Create the dialog box using DialogBox() or CreateDialog().

         DialogBox (hinst,
                    MAKEINTRESOURCE (IDD_MYDIALOG),
                    NULL,
                   (DLGPROC)MyDlgFunc);
   						

   MyDlgFunc() is the dialog function implemented by the application. When the dialog box is minimized, it will use the icon specified in the private class.