.NET 调用WINAPI 获取其他应用窗体内容

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace cstest
{
    public partial class Form1 : Form
    {
        public delegate bool CallBack(IntPtr hwnd, int lParam);
        private static CallBack myCallBack;
        public Form1()
        {
            myCallBack = new CallBack(Report);
        InitializeComponent();
           //获取窗口名称为C#的窗口句柄
            GetHandle("C#");
            this.textBox1.Multiline = true;
            this.textBox1.Dock = DockStyle.Fill;
        }

        private void GetHandle(string windcaption)
        {
            //调用WINAPI，根据名称取窗口句柄
            IntPtr mainHandle = FindWindow(null, windcaption);
            if (IntPtr.Zero != mainHandle)
            {
                AppendText(string.Format("{0}句柄：{1}", windcaption, Convert.ToString((int)mainHandle,16)));
                //枚举所有子窗体
                //EnumChildWindows((int)mainHandle, myCallBack, 0);
                //修改窗口标题为C++
                SetWindowText((int)mainHandle, "C++");
                StringBuilder s = new StringBuilder(512);
            //通过WINAPI获取控件标题，该方法不能获取到edit中的值，只能取button或窗体的caption
                int i = GetWindowText(mainHandle, s, s.Capacity);
                AppendText(string.Format("句柄{0}的caption：{1}", Convert.ToString((int)mainHandle, 16), s.ToString()));
           //枚举所有子窗体，并将子窗体句柄传给myCallBack
                EnumChildWindows((int)mainHandle, myCallBack, 0);
            }
        }

        //输出调试信息
        private void AppendText(string msg)
        {
            this.textBox1.AppendText(msg);
            this.textBox1.AppendText("
");
        }
        //根据句柄，输出句柄对应窗体的caption
        public bool Report(IntPtr hWnd, int lParam)
        {
            StringBuilder s = new StringBuilder(512);
            int i = GetWindowText((IntPtr)hWnd, s, s.Capacity);
            AppendText(string.Format("句柄{0}的caption：{1}", Convert.ToString((int)hWnd, 16), s.ToString()));
            return true;
        }

        /// <summary>
        /// 获取窗体的句柄函数
        /// </summary>
        /// <param name="lpClassName">窗口类名</param>
        /// <param name="lpWindowName">窗口标题名</param>
        /// <returns>返回句柄</returns>
        [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
        public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

        [DllImport("user32.dll")]
        public static extern int EnumWindows(CallBack x, int y);

        [DllImport("user32.dll")]
        private static extern IntPtr EnumChildWindows(int hWndParent, CallBack lpEnumFunc, int lParam);

        [DllImport("user32.dll")]
        public static extern int SetWindowText(int handle, string title);

        [DllImport("user32.dll", EntryPoint = "GetWindowText")]
        public static extern int GetWindowText(IntPtr hwnd, StringBuilder lpString,int cch);

        [DllImport("User32.dll", EntryPoint = "SendMessage")]
        private static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, StringBuilder lParam);

        private void button1_Click(object sender, EventArgs e)
        {
            StringBuilder s = new StringBuilder(512);
            //获取控件标题,对TRichEdit无效
            //int i = GetWindowText((IntPtr)int.Parse(txtHandle.Text), s, s.Capacity);
            //获取控件内容,对TRichEdit有效
            int i = SendMessage((IntPtr)int.Parse(txtHandle.Text), 0x000D, 1000, s);
            AppendText(string.Format("句柄{0}的caption：{1}", txtHandle.Text, s.ToString()));
        }
    }
}