How to handle WM_SETCURSOR in C#

问题

In my media player application, I hid the cursor using SetCursor(NULL) and to make sure that Windows does not reset the cursor state, I handled WM_SETCURSOR in my WndProc method.

protected override void WndProc(ref Message m)
{
    switch (m.Msg)
    {
        case WM.SETCURSOR:
            base.WndProc(ref m);
            int lowWord = (m.LParam.ToInt32() << 16) >> 16;
            if (lowWord == HTCLIENT && FullScreen)
            {
                SetCursor(IntPtr.Zero); // hides cursor
                m.Result = (IntPtr)1; // return TRUE; equivalent in C++
            }
            return;
    }
}

However when the cursor is in the client area (aka LOWORD(lParam) == HTCLIENT), WM_SETCURSOR is never triggered in WndProc. So I never actually get the WM_SETCURSOR message when the cursor is in the client area and only get it when LOWORD(lParam) != HTCLIENT.

However in Spy++, it clearly shows that the application received the WM_SETCURSOR and WM_MOUSEMOVE messages.

Where is the message getting lost/handled? What do I have to do in order to receive the WM_SETCURSOR message in C#?

回答1:

My application has several panels covering the application. So another user pointed out to me kindly that since every control has its own WndProc, the WM_SETCURSOR method wasn't being passed on to the form underneath it. In order to receive those messages, I would have to override each of those panels with its own WndProc method.

However the above code does work if there are no controls covering the form where the cursor is.

来源：https://stackoverflow.com/questions/18279938/how-to-handle-wm-setcursor-in-c-sharp

标签

winforms

wndproc