C# 嵌入第三方EXE界面到panel中

C#可以通过windows API，将第三方程序嵌入到panel中，并且可以隐藏程序边框。
问题：
焦点在内部程序时，主窗口失去焦点；

通讯解决方案

使用 User32.dll SendMessage 发送窗口级的 WM_COPYDATA 消息；使用 DefWndProc 处理消息；
来实现两个独立C#程序之间的通讯。

主程序代码如下：

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Diagnostics;

using System.Drawing;

using System.Linq;

using System.Runtime.InteropServices;

using System.Text;

using System.Threading;

using System.Windows.Forms;

namespace CallMain

{

    public partial class Form1 : Form

    {

        #region 外部DLL定义

        [DllImport("User32.dll", EntryPoint = "SetParent")]

        public static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);

        [DllImport("user32.dll", EntryPoint = "ShowWindow")]

        public static extern int ShowWindow(IntPtr hwnd, int nCmdShow);

        [DllImport("user32.dll", SetLastError = true)]

        public static extern bool MoveWindow(IntPtr hwnd, int x, int y, int cx, int cy, bool repaint);

        [DllImport("user32.dll")]

        public static extern int GetWindowLong(IntPtr hWnd, int nIndex);

        [DllImport("user32.dll")]

        public static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);

        const int WS_THICKFRAME = ;

        const int WS_BORDER = ;

        const int GWL_STYLE = -;

        [DllImport("User32.dll")]

        public static extern int SendMessage(IntPtr hwnd, int msg, IntPtr wParam, ref COPYDATASTRUCT IParam);

        public const int WM_COPYDATA = 0x004A;

        public struct COPYDATASTRUCT

        {

            public IntPtr dwData;

            public int cbData;

            [MarshalAs(UnmanagedType.LPStr)]

            public string lpData;

        }

        // 发送 windows 消息

        public void SendMsg(IntPtr hwnd, string str)

        {

            byte[] arr = Encoding.Default.GetBytes(str);

            int len = arr.Length;

            COPYDATASTRUCT cdata;

            cdata.dwData = (IntPtr);

            cdata.lpData = str;

            cdata.cbData = len + ;

            SendMessage(hwnd, WM_COPYDATA, this.Handle, ref cdata);

        }

        public delegate void EventMsg(object sender, IntPtr wnd, string str);

        public event EventMsg OnMsg;

        // 进程间消息通讯

        protected override void DefWndProc(ref Message m)

        {

            switch (m.Msg)

            {

                case WM_COPYDATA:

                    COPYDATASTRUCT cdata = new COPYDATASTRUCT();

                    Type mytype = cdata.GetType();

                    cdata = (COPYDATASTRUCT)m.GetLParam(mytype);

                    OnMsg(this, m.WParam, cdata.lpData);

                    break;

                default:

                    base.DefWndProc(ref m);

                    break;

            }

        }

        #endregion

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            this.OnMsg += Form1_OnMsg; ;

        }

        private void Form1_OnMsg(object sender, IntPtr wnd, string str)

        {

            // 接收消息处理

            SendMsg(wnd, "收到了子窗口消息：" + str);

        }

        private void button1_Click(object sender, EventArgs e)

        {

            Process proApp = new Process();

            proApp.StartInfo.FileName = Application.StartupPath + "\\CallTest.exe";

            proApp.StartInfo.WindowStyle = ProcessWindowStyle.Minimized;

            proApp.Start();

            proApp.WaitForInputIdle();

            while (proApp.MainWindowHandle == IntPtr.Zero)

            {

                Thread.Sleep();

                proApp.Refresh();

            }

            IntPtr wnd = proApp.MainWindowHandle;

            Int32 wndStyle = GetWindowLong(wnd, GWL_STYLE);

            wndStyle &= ~WS_BORDER;

            wndStyle &= ~WS_THICKFRAME;

            SetWindowLong(wnd, GWL_STYLE, wndStyle);

            SetParent(wnd, panel1.Handle);

            ShowWindow(wnd, (int)ProcessWindowStyle.Maximized);

            panel1.Tag = proApp;

            SendMsg(wnd, "hi");

        }

        private void button2_Click(object sender, EventArgs e)

        {

            // 给子窗口发消息

            Process proApp = (Process)panel1.Tag;

            SendMsg(proApp.MainWindowHandle, "hello 子窗口");

        }

    }

}

子程序通讯代码

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.Windows.Forms;

namespace CallTest

{

    public partial class Form1 : Form

    {

        #region 消息通讯

        [DllImport("User32.dll")]

        public static extern int SendMessage(IntPtr hwnd, int msg, IntPtr wParam, ref COPYDATASTRUCT IParam);

        const int WM_COPYDATA = 0x004A;

        public struct COPYDATASTRUCT

        {

            public IntPtr dwData;

            public int cbData;

            [MarshalAs(UnmanagedType.LPStr)]

            public string lpData;

        }

        private IntPtr MainWnd = IntPtr.Zero;

        public delegate void EventMsg(object sender, string str);

        public event EventMsg OnMsg;

        //发送消息

        private void SendMsg(string str)

        {

            if (MainWnd == IntPtr.Zero)

            {

                return;

            }

            byte[] arr = Encoding.Default.GetBytes(str);

            int len = arr.Length;

            COPYDATASTRUCT cdata;

            cdata.dwData = (IntPtr);

            cdata.lpData = str;

            cdata.cbData = len + ;

            SendMessage(MainWnd, WM_COPYDATA, this.Handle, ref cdata);

        }

        protected override void DefWndProc(ref Message m)

        {

            switch (m.Msg)

            {

                case WM_COPYDATA:

                    COPYDATASTRUCT cdata = new COPYDATASTRUCT();

                    Type mytype = cdata.GetType();

                    cdata = (COPYDATASTRUCT)m.GetLParam(mytype);

                    MainWnd = m.WParam;

                    OnMsg(this, cdata.lpData);

                    break;

                default:

                    base.DefWndProc(ref m);

                    break;

            }

        }

        #endregion

        public Form1()

        {

            InitializeComponent();

        }

        private int index = ;

        private void button1_Click(object sender, EventArgs e)

        {

            // 发送消息

            index++;

            SendMsg("收到啦！" + index);

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            this.OnMsg += Form1_OnMsg;

        }

        private void Form1_OnMsg(object sender, string str)

        {

            // 接收消息

            if (str == "hi")

            {

                SendMsg("hi");

                return;

            }

            label1.Text = str;

            label2.Text = MainWnd.ToString("x");

        }

    }

}