Question

I am trying to get the mouse cords after using a WndProc hook to get messages from Win32 API..

Below is my code.. Its not long, and should be easy enough to understand..
I am learning all this as I go and just can’t figure out how to change the lParam to points x and y..

Any help would be nice, Thanks 🙂

    private const int WM_LEFTBUTTONDOWN = 0x0201;
    private const int WM_LEFTBUTTONUP = 0x0202;
    private const int WM_MOUSEMOVE = 0x0200;
    private const int WM_MOUSEWHEEL = 0x020A;
    private const int WM_RIGHTBUTTONDOWN = 0x0204;
    private const int WM_RIGHTBUTTONUP = 0x0205;


    public MainWindow()
    {
        InitializeComponent();
    }

    protected override void OnSourceInitialized(EventArgs e)
    {
        base.OnSourceInitialized(e);
        HwndSource source = PresentationSource.FromVisual(this) as HwndSource;
        source.AddHook(WndProc);
    }

    private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
    {

        if (msg == WM_MOUSEMOVE)
        {
            label1.Content = "Msg: " + msg + " wParam: " + wParam + " lParam: " + lParam;
        }

        return IntPtr.Zero;
    }

Answer 1

The x coordinate is in the low 16 bits, the y in the next 16 bits. Crack it like this:

int x = (short)lParam.ToInt32();
int y = lParam.ToInt32() >> 16;