c# 自定义消息 进程间通信

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Diagnostics;

namespace TopInfo.Metevation.Common
{
//WM_COPYDATA消息所要求的数据结构
public struct CopyDataStruct
{
public IntPtr dwData;
public int cbData;

[MarshalAs(UnmanagedType.LPStr)]
public string lpData;
}

/// 本类封装了一些进程间通讯的细节
public class WINMessageUtil
{
public const int WM_COPYDATA = 0x004A;

//通过窗口的标题来查找窗口的句柄
[DllImport("User32.dll", EntryPoint = "FindWindow")]
private static extern int FindWindow(string lpClassName, string lpWindowName);

//在DLL库中的发送消息函数
[DllImport("User32.dll", EntryPoint = "SendMessage")]
private static extern int SendMessage
(
int hWnd,                        // 目标窗口的句柄
int Msg,                        // 在这里是WM_COPYDATA
int wParam,                    // 第一个消息参数
ref  CopyDataStruct lParam        // 第二个消息参数
);

/// 发送消息，只能传递一个自定义的消息ID和消息字符串，想传一个结构，但没成功
/// 目标进程名称，如果有多个，则给每个都发送
/// 自定义数据，可以通过这个来决定如何解析下面的strMsg
/// 传递的消息，是一个字符串
public static void SendMessage(int toWndHandler, string strMsg)
{
string s = toWndHandler.ToString();
if (strMsg == null) return;

int toWindowHandler = FindWindow(null, "置顶自动观测站服务");//获取目标窗口句柄方法一

//获取目标窗口句柄方法二
//Process[] foundProcess = Process.GetProcessesByName("TopInfo.Metevation.Controller.Services.exe");
//foreach (Process p in foundProcess)
//{
//    toWndHandler = p.MainWindowHandle.ToInt32();
//}

// SystemEventLog.Log.WriteEntry(s + "获得句柄aaa" + toWndHandler);

CopyDataStruct cds;
cds.dwData = (IntPtr)100;   //这里可以传入一些自定义的数据，但只能是4字节整数
cds.lpData = strMsg;            //消息字符串
cds.cbData = System.Text.Encoding.Default.GetBytes(strMsg).Length + 1;  //注意，这里的长度是按字节来算的

//发送方的窗口的句柄, 由于本系统中的接收方不关心是该消息是从哪个窗口发出的，所以就直接填0了
int fromWindowHandler = 0;
SendMessage(toWndHandler, WM_COPYDATA, fromWindowHandler, ref  cds);
}

/// 接收消息，得到消息字符串
/// System.Windows.Forms.Message m
/// 接收到的消息字符串
public static string ReceiveMessage(ref  System.Windows.Forms.Message m)
{
CopyDataStruct cds = (CopyDataStruct)m.GetLParam(typeof(CopyDataStruct));
return cds.lpData;
}
}
}

protected override void DefWndProc(ref System.Windows.Forms.Message m)
{
switch (m.Msg)
{
case WINMessageUtil.WM_COPYDATA:
string msg = WINMessageUtil.ReceiveMessage(ref m);
PrintMessage(msg);
break;
default:
base.DefWndProc(ref m);
break;
}
}