C#•2mo ago

win32 island in wpf application has #f0f0f0 background colour

hii!! i'm working on a project which requires an embedded win32 control. however, the background of the island is always #f0f0f0 instead of #ffffff. this occurs even if the window is hosting no control and is just a child window. see the attached image for an example

2 Replies

nullptrOP•2mo ago

(the only parts in ControlHost which matter in this instance are BuildWindowCore and WndProc, which i'll provide below)

protected override HandleRef BuildWindowCore(HandleRef hwndParent)
{
    // this is just for testing to see if command links are the problem (they aren't - the bg is still #f0f0f0)
    hwndControl = CreateWindowEx(0, "static", "This half of the window is being rendered by a Win32 island via HwndHost. Notice how the background is #f0f0f0.",
                                  WindowStyles.WS_VISIBLE | WindowStyles.WS_CHILD,
                                  0, 0,
                                  hostWidth, hostHeight,
                                  hwndParent.Handle,
                                  IntPtr.Zero,
                                  IntPtr.Zero,
                                  0);

    return new HandleRef(this, hwndControl.DangerousGetHandle());
}

protected override IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
    handled = false;
    return IntPtr.Zero;
}

protected override HandleRef BuildWindowCore(HandleRef hwndParent)
{
    // this is just for testing to see if command links are the problem (they aren't - the bg is still #f0f0f0)
    hwndControl = CreateWindowEx(0, "static", "This half of the window is being rendered by a Win32 island via HwndHost. Notice how the background is #f0f0f0.",
                                  WindowStyles.WS_VISIBLE | WindowStyles.WS_CHILD,
                                  0, 0,
                                  hostWidth, hostHeight,
                                  hwndParent.Handle,
                                  IntPtr.Zero,
                                  IntPtr.Zero,
                                  0);

    return new HandleRef(this, hwndControl.DangerousGetHandle());
}

protected override IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
    handled = false;
    return IntPtr.Zero;
}

Omnissiah•2mo ago

but did you set the background brush? (iirc)

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win32 island in wpf application has #f0f0f0 background colour