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The WM_QUERYDRAGICON message is sent to a minimized (iconic) window. The window is about to be dragged by the user but does not have an icon defined for its class. An application can return a handle to an icon or cursor. The system displays this cursor or icon while the user drags the icon.
A window receives this message through its WindowProc function.
LRESULT CALLBACK WindowProc(
HWND hwnd, // handle to window
UINT uMsg, // WM_QUERYDRAGICON
WPARAM wParam, // not used
LPARAM lParam // not used
);
This message has no parameters.
An application should return a handle to a cursor or icon that the system is to display while the user drags the icon. The cursor or icon must be compatible with the display driver's resolution. If the application returns NULL, the system displays the default cursor.
When the user drags the icon of a window without a class icon, the system replaces the icon with a default cursor. If the application requires a different cursor to be displayed during dragging, it must return a handle to the cursor or icon compatible with the display driver's resolution. If an application returns a handle to a color cursor or icon, the system converts the cursor or icon to black and white. The application can call the LoadCursor or LoadIcon function to load a cursor or icon from the resources in its executable (.EXE) file and to retrieve this handle.
If a dialog box procedure handles this message, it should cast the desired return value to a BOOL and return the value directly. The DWL_MSGRESULT value set by the SetWindowLong function is ignored.
Windows NT/2000 or later: Requires Windows NT 3.1 or later. Windows 95/98/Me: Requires Windows 95 or later. Header: Declared in Winuser.h; include Windows.h.
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Notebook exported on Monday, 7 July 2008, 18:56:50 PM Eastern Daylight Time