send mouse click
<p>I am trying to simulate mouse click without using mouse by sendmessage
somehow it not working but there is no error show.
here is my new code</p>

<pre><code>using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Input;
using System.Diagnostics;


namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        private const int BM_CLICK = 0x00F5;

        [DllImport("user32.dll", SetLastError = true)]
        static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

        [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
        static extern IntPtr FindWindowByCaption(IntPtr ZeroOnly, string lpWindowName);

        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern IntPtr FindWindowEx(IntPtr parentHandle, IntPtr childAfter, string className, string windowTitle);

    public Form1()
    {
        InitializeComponent();
    }



        private void button1_Click(object sender, EventArgs e)
        {
            IntPtr hwndChild = IntPtr.Zero;
            IntPtr hwnd = IntPtr.Zero;
            hwnd = FindWindow(null, "MSPaintApp");
            hwndChild = FindWindowEx(hwnd, IntPtr.Zero, "Afx:00007FF765740000:8", null);
            SendMessage(hwndChild, BM_CLICK, IntPtr.Zero, IntPtr.Zero);
        }
    }
}
</code></pre>

<p>Can you someone show me how to put X Y coordination that it will click on a child window. I saw many post teaching how to do that but i can't know understand it and the system said do not ask question in other people question :(</p>