How do you place sub controls inside a group box? - c

Question

When I enable common control visual style support (InitCommonControls()) and I am using any theme other then Windows Classic Theme, buttons inside a group box appear with a black border with square corners.
Windows Classic Theme appears normal, as well as when I turn off visual styling.
I am using the following code:
group_box = CreateWindow(TEXT("BUTTON"), TEXT("BS_GROUPBOX"),
WS_CHILD | WS_VISIBLE | BS_GROUPBOX | WS_GROUP,
10, 10, 200, 300,
hwnd, NULL, hInstance, 0);
push_button = CreateWindow(TEXT("BUTTON"), TEXT("BS_PUSHBUTTON"),
WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
40, 40, 100, 22,
group_box, NULL, hInstance, 0);
EDIT: The issue occurs with radio buttons as well
EDIT: I am not using any dialogs/resources, only CreateWindow/Ex.
I am compiling under Visual C++ 2008 Express SP1, with a generic manifest file
Screenshot http://img.ispankcode.com/black_border_issue.png

Answer 1

The problem is having the groupbox as the controls' parent. Groupboxes are not supposed to have any children and using them as parents will cause all kinds of errors (including painting, keyboard navigation and message propagation). Just change the parent in the buttons' CreateWindow call from group_box to hwnd (i.e. the dialog).
I'm guessing you used the groupbox as the parent in order to position the other controls easily inside it. The proper way to do this is to get the position of the groupbox client area and map it to the client area of the dialog. Everything placed in the resulting RECT will then appear inside the groupbox. Since groupboxes don't actually have a client area, it can be calculated with something like this:
// Calculate the client area of a dialog that corresponds to the perceived
// client area of a groupbox control. An extra padding in dialog units can
// be specified (preferably in multiples of 4).
//
RECT getClientAreaInGroupBox(HWND dlg, int id, int padding = 0) {
HWND group = GetDlgItem(dlg, id);
RECT rc;
GetWindowRect(group, &rc);
MapWindowPoints(0, dlg, (POINT*)&rc, 2);
// Note that the top DUs should be 9 to completely avoid overlapping the
// groupbox label, but 8 is used instead for better alignment on a 4x4
// design grid.
RECT border = { 4, 8, 4, 4 };
OffsetRect(&border, padding, padding);
MapDialogRect(dlg, &border);
rc.left += border.left;
rc.right -= border.right;
rc.top += border.top;
rc.bottom -= border.bottom;
return rc;
}
Note that the same applies to Tab controls. They too are not designed to be parents and will exhibit similar behavior.

Answer 2

Just a guess here, but it looks like you are inheriting either the Static Edge or Client Edge style from you theme. I create most of my dialogs from the resource editor and set these properties there.
In your case, you can replace your CreateWindow with a CreateWindowEx to set these extended styles, which are probably being defaulted in CreateWindow. Specifically check out WS_EX_STATICEDGE, WS_EX_WINDOWEDGE and WS_EX_CLIENTEDGE
Edit: I'm assuming that this is not happening because you button is the default control in the dialog, which would also give a black edge.

Answer 3

Apparently group boxes are not meant to group controls (be a parent hwnd)
So in order to get rid of the black borders/painting issues I would have to subclass group box and implement WM_PAINT and WM_PRINTCLIENT

Answer 4

Ahh yes the black background with radio buttons and group boxes. Although I'm not sure if this will work for VC++ 2008, but back-in-the-day the solution for VB6 themed apps was to put the radio controls on a PictureBox (a generic container really) first and then add that to the group box.
Its worth a shot!