在Wince/WM实现进程间通信

本文来自http://blog.csdn.net/hellogv/ ，引用必须注明出处！

最近在做WM上的进程间通信，使用WindowMessage实现两个进程间的通信，感觉MessageWindow不太好用，所以就用别的方法实现接收WindowsMessage。本文的代码大部分来自网络，东凑西凑才拼成本文。

先来封装一下需要使用的功能，命名为Cls_Message:

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using Microsoft.WindowsCE.Forms;
using System.Windows.Forms;
class Cls_Message
{
    private struct COPYDATASTRUCT
    {
        public int dwData;
        public int cbData;
        public IntPtr lpData;
    }
    //-------------------------------------------------------------------------------
    private const int WM_COPYDATA = 0x004A;
    private const int GWL_WNDPROC = -4;
    private const int LMEM_FIXED = 0x0000;
    private const int LMEM_ZEROINIT = 0x0040;
    private const int LPTR = (LMEM_FIXED | LMEM_ZEROINIT);
    private  IntPtr oldWndProc = IntPtr.Zero;
    private  WndProcDelegate newWndProc;
    private IntPtr formHandle;
    //-------------------------------------------------------------------------------
    delegate IntPtr WndProcDelegate(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);
    [DllImport("coredll.dll")]
    static extern IntPtr CallWindowProc(IntPtr lpPrevWndFunc, IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);
    [DllImport("coredll.dll", EntryPoint = "GetWindowLong")]
    private static extern IntPtr GetWindowLong(IntPtr hWnd, int nIndex);
    [DllImport("coredll.dll")]
    static extern int SetWindowLong(IntPtr hWnd, int nIndex, IntPtr newWndProc);
    [DllImport("coredll.dll", EntryPoint = "FindWindow")]
    public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
    [DllImport("coredll.dll")]
    private static extern int SendMessageW(IntPtr hWnd, int Msg, IntPtr wParam, IntPtr lParam);
    [DllImport("coredll.dll")]
    private static extern IntPtr LocalAlloc(int flag, int size);
    [DllImport("coredll.dll")]
    private static extern IntPtr LocalFree(IntPtr p);
    /// <summary>
    /// 初始化消息类
    /// </summary>
    /// <param name="handle">接受消息的窗体的句柄</param>
    public Cls_Message(IntPtr formHandle)
    {
        this.formHandle = formHandle;
        newWndProc = new WndProcDelegate(WndProc);
        oldWndProc = GetWindowLong(formHandle, GWL_WNDPROC);
        int success = SetWindowLong(formHandle, GWL_WNDPROC, Marshal.GetFunctionPointerForDelegate(newWndProc));
    }
    /// <summary>
    /// 消息处理
    /// </summary>
    private IntPtr WndProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam)
    {
        if (msg == WM_COPYDATA)
        {
            COPYDATASTRUCT st = (COPYDATASTRUCT)Marshal.PtrToStructure(lParam, typeof(COPYDATASTRUCT));
            string str = Marshal.PtrToStringUni(st.lpData);
            MessageBox.Show(str);
        }
        return CallWindowProc(oldWndProc, this.formHandle, msg, wParam, lParam);
    }
    
    static private IntPtr AllocHGlobal(int cb)
    {
        IntPtr hMemory = new IntPtr();
        hMemory = LocalAlloc(LPTR, cb);
        return hMemory;
    }
    static private void FreeHGlobal(IntPtr hMemory)
    {
        if (hMemory != IntPtr.Zero)
            LocalFree(hMemory);
    }
    /// <summary>
    /// 发送消息
    /// </summary>
    /// <param name="formTitle">目标窗体的名称</param>
    /// <param name="message">消息内容</param>
    static public void SendMessage(String formTitle,String message)
    {
        IntPtr hWndDest = FindWindow(null, formTitle);
        COPYDATASTRUCT oCDS = new COPYDATASTRUCT();
        oCDS.cbData = (message.Length + 1) * 2;
        oCDS.lpData = LocalAlloc(LPTR, oCDS.cbData);
        Marshal.Copy(message.ToCharArray(), 0, oCDS.lpData, message.Length);
        oCDS.dwData = 1;
        IntPtr lParam = AllocHGlobal(oCDS.cbData);
        Marshal.StructureToPtr(oCDS, lParam, false);
        SendMessageW(hWndDest, WM_COPYDATA, IntPtr.Zero, lParam);
        LocalFree(oCDS.lpData);
        FreeHGlobal(lParam);
    }
}

接下来贴出调用代码，实现自发自收，如果要发给别的进程，只需要把SendMessage的第一个参数改为目标窗体的名称即可（当然目标窗体也必须引用了Cls_Message实现收信息处理）：

        Cls_Message clsMessage;//初始化
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            clsMessage = new Cls_Message(this.Handle);//使本窗体能够接收WindowMessage
        }
        private void button1_Click(object sender, EventArgs e)
        {
            Cls_Message.SendMessage("Form1", "hello form1");
        }