- 1 year ago
How do I use WM_CTLCOLORLISTBOX?
The WM_CTLCOLORLISTBOX
message is used in Windows programming to customize the appearance of a list box control (ListBox
) in response to the WM_CTLCOLOR
message.
To use WM_CTLCOLORLISTBOX
, you need to handle the WM_CTLCOLOR
message in the parent window procedure and return the desired HBRUSH
handle that represents the brush used for painting the list box background and text.
Here's an example of how you can use WM_CTLCOLORLISTBOX
in a Windows application:
c++LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
// Handle the WM_CTLCOLOR message
case WM_CTLCOLOR:
{
HDC hdc = reinterpret_cast<HDC>(wParam);
HWND hWndControl = reinterpret_cast<HWND>(lParam);
if (GetDlgItem(hWnd, ID_LISTBOX) == hWndControl)
{
HBRUSH hBrush = CreateSolidBrush(RGB(255, 0, 0)); // Red brush as an example
// Set the background and text color of the list box
SetBkColor(hdc, RGB(255, 0, 0)); // Red background color
SetTextColor(hdc, RGB(255, 255, 255)); // White text color
return reinterpret_cast<LRESULT>(hBrush);
}
break;
}
// Other message handling code...
}
return DefWindowProc(hWnd, message, wParam, lParam);
}
In this example, we handle the WM_CTLCOLOR
message in the parent window procedure (WindowProc
). We check if the control handle matches the desired list box control (ID_LISTBOX
). If it does, we create a red brush (CreateSolidBrush
) and set the background color (SetBkColor
) and text color (SetTextColor
) of the list box. Finally, we return the handle of the created brush.
Ensure that you have the necessary window and message handling code in your application and replace ID_LISTBOX
with the actual identifier of your list box control.
Note that WM_CTLCOLORLISTBOX
is a specific part of the WM_CTLCOLOR
message and is called when the list box control is being painted. Make sure to handle other messages appropriately in your window procedure.
Remember to manage the resources properly by destroying the brush handle (DeleteObject
) when it is no longer needed.
This example is written in C++, but similar concepts can be applied in other programming languages when using the Windows API for message handling.