Question

I would like to create very simple program that could help my relative to see the mouse pointer with using large object in specific contrast color. So I would need the object to be present still on the top of all running apps and on the mouse x,y.
I have alredy find a code that recieves mouse coordinates from outside of the app, but I have no clue how to continue. THanks!

EDIT: This is the mouse hook code that prints or just store X,Y of mouse cursor. That is all I have – I have no idea how to create an object and display it “above” all other apps.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
    class Class1
    {
        class InterceptMouse
        {
            private static LowLevelMouseProc _proc = HookCallback;
            private static IntPtr _hookID = IntPtr.Zero;

            public static void Main()
            {
                _hookID = SetHook(_proc);
                Application.Run();
                UnhookWindowsHookEx(_hookID);
            }

            private static IntPtr SetHook(LowLevelMouseProc proc)
            {
                using (Process curProcess = Process.GetCurrentProcess())
                using (ProcessModule curModule = curProcess.MainModule)
                {
                    return SetWindowsHookEx(WH_MOUSE_LL, proc,
                        GetModuleHandle(curModule.ModuleName), 0);
                }
            }

            private delegate IntPtr LowLevelMouseProc(int nCode, IntPtr wParam, IntPtr lParam);

            private static IntPtr HookCallback(
                int nCode, IntPtr wParam, IntPtr lParam)
            {
                if (nCode >= 0 &&
                    MouseMessages.WM_LBUTTONDOWN == (MouseMessages)wParam)
                {
                    MSLLHOOKSTRUCT hookStruct = (MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(MSLLHOOKSTRUCT));
                    Console.WriteLine(hookStruct.pt.x + ", " + hookStruct.pt.y);
                }
                return CallNextHookEx(_hookID, nCode, wParam, lParam);
            }

            private const int WH_MOUSE_LL = 14;

            private enum MouseMessages
            {
                WM_LBUTTONDOWN = 0x0201,
                WM_LBUTTONUP = 0x0202,
                WM_MOUSEMOVE = 0x0200,
                WM_MOUSEWHEEL = 0x020A,
                WM_RBUTTONDOWN = 0x0204,
                WM_RBUTTONUP = 0x0205
            }

            [StructLayout(LayoutKind.Sequential)]
            private struct POINT
            {
                public int x;
                public int y;
            }

            [StructLayout(LayoutKind.Sequential)]
            private struct MSLLHOOKSTRUCT
            {
                public POINT pt;
                public uint mouseData;
                public uint flags;
                public uint time;
                public IntPtr dwExtraInfo;
            }

            [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
            private static extern IntPtr SetWindowsHookEx(int idHook,
                LowLevelMouseProc lpfn, IntPtr hMod, uint dwThreadId);

            [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
            [return: MarshalAs(UnmanagedType.Bool)]
            private static extern bool UnhookWindowsHookEx(IntPtr hhk);

            [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
            private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
                IntPtr wParam, IntPtr lParam);

            [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
            private static extern IntPtr GetModuleHandle(string lpModuleName);
        }

    }
}

Answer 1

Listen to WM_MOUSEMOVE