C# 窗口捕捉 句柄

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;

namespace getWindowApp
{
    public partial class Form1 : Form
    {
        public Form1（）
        {
            InitializeComponent（）;
            btnStart.Enabled = true;
            btnStop.Enabled = false;
            this.TopMost = true;
        }


        [DllImport（“User32.dll“CallingConvention = CallingConvention.StdCall）]
        public extern static IntPtr WindowFromPoint（int x int y）;

        [DllImport（“User32.dll“ CallingConvention = CallingConvention.StdCall）]
        public extern static int G

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     目录           0  2013-05-26 17:30  getWindowApp\
     目录           0  2013-05-27 17:19  getWindowApp\getWindowApp\
     文件         954  2013-05-26 17:30  getWindowApp\getWindowApp.sln
     文件       36352  2013-05-27 17:13  getWindowApp\getWindowApp.v11.suo
     文件         187  2013-05-26 17:30  getWindowApp\getWindowApp\App.config
     文件        3807  2013-05-27 16:48  getWindowApp\getWindowApp\Form1.cs
     文件        8735  2013-05-27 16:48  getWindowApp\getWindowApp\Form1.Designer.cs
     文件        6012  2013-05-27 16:48  getWindowApp\getWindowApp\Form1.resx
     文件        3857  2013-05-27 16:09  getWindowApp\getWindowApp\getWindowApp.csproj
     文件         524  2013-05-26 17:30  getWindowApp\getWindowApp\Program.cs
     目录           0  2013-05-26 17:30  getWindowApp\getWindowApp\Properties\
     文件        1344  2013-05-26 17:30  getWindowApp\getWindowApp\Properties\AssemblyInfo.cs
     文件        2876  2013-05-26 17:30  getWindowApp\getWindowApp\Properties\Resources.Designer.cs
     文件        5612  2013-05-26 17:30  getWindowApp\getWindowApp\Properties\Resources.resx
     文件        1099  2013-05-26 17:30  getWindowApp\getWindowApp\Properties\Settings.Designer.cs
     文件         249  2013-05-26 17:30  getWindowApp\getWindowApp\Properties\Settings.settings