這個小程序需要用到系統API，也就是需要用到user32中的三個函數。
第一個：WindowFromPoint 返回一個窗口句柄
第二個：GetWindowText??獲取窗口標題
第三個：GetClassName??獲取類名
當然，最重要的一點就是要引用命名空間：using System.Runtime.InteropServices;
先來看看做出來的效果：

在來看看源碼：
------------------源碼部分-------------------------
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace prjCursorHandler
{
????public partial class Form1 : Form
????{
????????//獲取窗口標題
????????[DllImport("user32", SetLastError = true)]
????????public static extern int GetWindowText(
????????IntPtr hWnd,?//窗口句柄
????????StringBuilder lpString,?//標題
????????int nMaxCount ?//最大值
????????);
????????//獲取類的名字
????????[DllImport("user32.dll")]
????????private static extern int GetClassName(
????????????IntPtr hWnd, //句柄
????????????StringBuilder lpString, //類名
????????????int nMaxCount //最大值
????????);
????????//根據坐標獲取窗口句柄
????????[DllImport("user32")]
????????private static extern IntPtr WindowFromPoint(
????????Point Point ?//坐標
????????);
????????public Form1()
????????{
????????????InitializeComponent();
????????}
????????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);//得到窗口的標題
????????????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 + "窗口標題:" + title + Environment.NewLine + "類名:" + className;
????????}

????????private void textBox1_KeyDown(object sender, KeyEventArgs e)
????????{
????????????if(e.KeyCode==Keys.Enter || e.KeyCode==Keys.Space)
????????????{
????????????????this.button1.PerformClick();
????????????}
????????}
????}
}