Processing a Double-Click Message

To receive double-click messages, a window must belong to a window class that has the CS_DBLCLKS class style. You set this style when registering the window class, as shown in the following example.

BOOL InitApplication(hInstance)

HINSTANCE hInstance;

{

WNDCLASS wc;

wc.style = CS_DBLCLKS | CS_HREDRAW | CS_VREDRAW;

wc.lpfnWndProc = (WNDPROC) MainWndProc;

wc.cbClsExtra = 0;

wc.cbWndExtra = 0;

wc.hInstance = hInstance;

wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);

wc.hCursor = LoadCursor(NULL, IDC_IBEAM);

wc.hbrBackground = GetStockObject(WHITE_BRUSH);

wc.lpszMenuName = "MainMenu";

wc.lpszClassName = "MainWClass";

return RegisterClass(&wc);

}

A double-click message is always preceded by a button down message. For this reason, applications typically use a double-click message to extend a task that it began during a button down message.