Screen coordinates for cursor never close to 0

Question

I am using the user32.dll function GetCursorPos to get the SCREEN coordinates of my cursor. I need to know if the cursor is at the top of the screen (with multiple monitor setups included).

However, when I try to test for the Y coordinate that GetCursorPos gives me, I never got a coordinate less than 250 or so, even though I moved the cursor around all the screen borders of both my screens.

I have thought the upper left corner of my main screen would be [0,0] and Y would grow as I got lower on my screen, why does it start with such a high number?

    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    static extern bool GetCursorPos(out POINT lpPoint);


    [StructLayout(LayoutKind.Sequential)]
    public struct POINT
    {
        public int X;
        public int Y;

        public POINT(int x, int y)
        {
            this.X = x;
            this.Y = y;
        }
    }


    private void Whatever() {
       POINT lMousePosition;

       GetCursorPos(out lMousePosition)
    }

I expect the output of the function to be less than 10 in the Y coordinate somewhere... its not. Why?

EDIT:

I have found the solution. The function returns the correct values, but my usage of breakpoints to look at the said value changed it from the one I wanted to saw when the breakpoint got hit.

score -1 · Answer 1 · answered Aug 27 '19 at 15:07

I edited the question so its also there...

The problem was caused by breakpoints making the function to evaluate later than I expected and moving my cursor in the process. Therefore the values I saw while debugging were the correct values at that time.

Screen coordinates for cursor never close to 0

1 Answers1