好东西，自己看

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.Runtime.InteropServices;namespace CS_Control{    public partial class Form1 : Form    {        //获取窗口标题        [DllImport("user32", SetLastError = true)]        public static extern int GetWindowText(        IntPtr hWnd, //窗口句柄        StringBuilder lpString, //标题        int nMaxCount  //最大值        );        //获取类的名字        [DllImport("user32.dll")]        private static extern int GetClassName(            IntPtr hWnd, //句柄            StringBuilder lpString, //类名            int nMaxCount //最大值        );        //根据坐标获取窗口句柄        [DllImport("user32")]        private static extern IntPtr WindowFromPoint(        Point Point  //坐标        );        [DllImport("User32.dll", EntryPoint = "FindWindow")]        private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);        [DllImport("user32.dll", EntryPoint = "FindWindowEx")]        private static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);        [DllImport("User32.dll", EntryPoint = "SendMessage")]        private static extern int SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, string lParam);         const int WM_GETTEXT = 0x000D;        const int WM_SETTEXT = 0x000C;        const int WM_CLICK = 0x00F5;        public Form1()        {            InitializeComponent();        }        private void Form1_Load(object sender, EventArgs e)        {        }        private void button1_Click(object sender, EventArgs e)        {            this.timer1.Enabled = !this.timer1.Enabled;        }        private void timer1_Tick(object sender, EventArgs e)        {            int x = Cursor.Position.X;            int y = Cursor.Position.Y;            Point p = new Point(x, y);            IntPtr formHandle = WindowFromPoint(p);//得到窗口句柄            StringBuilder title = new StringBuilder(256);            GetWindowText(formHandle, title, title.Capacity);//得到窗口的标题            StringBuilder className = new StringBuilder(256);            GetClassName(formHandle, className, className.Capacity);//得到窗口的句柄            this.textBox1.Text = "窗口句柄:" + formHandle.ToString() + Environment.NewLine + "窗口标题:" + title + Environment.NewLine + "类名:" + className;            temp = formHandle;            textBox_jubing.Text = temp.ToString();            //string w = "";            //IntPtr ptr = Marshal.StringToHGlobalAnsi(w);                        //SendMessage(formHandle, WM_SETTEXT, IntPtr.Zero, "hello");                     }        private void textBox1_KeyDown(object sender, KeyEventArgs e)        {            if (e.KeyCode == Keys.Enter || e.KeyCode == Keys.Space)            {                this.button1.PerformClick();            }        }        IntPtr temp;        private void button2_Click(object sender, EventArgs e)        {            textBox3.Text = "";            //textBox_jubing.Text = "";            //SendMessage(temp, WM_SETTEXT, IntPtr.Zero, "hello");         }        private void textBox3_MouseDown(object sender, MouseEventArgs e)        {            //MessageBox.Show("!");            SendMessage(temp, WM_SETTEXT, IntPtr.Zero, "hello");         }    }}