EXE之间传递消息

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;

namespace WinFormSendMsg
{
    partial class Form1 : System.Windows.Forms.Form
    {
        private System.Windows.Forms.TextBox textBox1;
        private System.Windows.Forms.Button button1;

        const int WM_COPYDATA = 0x004A;


        public Form1()
        {
            InitializeComponent();
        }

        [DllImport("User32.dll", EntryPoint = "SendMessage")]
        private static extern int SendMessage(
        int hWnd, // handle to destination window
        int Msg, // message
        int wParam, // first message parameter
        ref COPYDATASTRUCT lParam // second message parameter
        );


        [DllImport("User32.dll", EntryPoint = "FindWindow")]
        private static extern int FindWindow(string lpClassName, string
        lpWindowName);


        private void button1_Click(object sender, System.EventArgs e)
        {
            int WINDOW_HANDLER = FindWindow(null, @"接收方窗体");
            if (WINDOW_HANDLER == 0)
            {
            }
            else
            {
                byte[] sarr = System.Text.Encoding.Default.GetBytes(this.textBox1.Text);
                int len = sarr.Length;

                COPYDATASTRUCT cds;
                cds.dwData = (IntPtr) 100;
                cds.lpData = this.textBox1.Text;
                cds.cbData = len + 1;
                SendMessage(WINDOW_HANDLER, WM_COPYDATA, 0, ref cds);
            }

        }
    }

    public struct COPYDATASTRUCT
    {
        public IntPtr dwData;
        public int cbData;
        [MarshalAs(UnmanagedType.LPStr)]
        public string lpData;
    }
}

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;

namespace WindowsFormGetMsg
{
    partial class Form1 : System.Windows.Forms.Form
    {
        private System.Windows.Forms.TextBox textBox1;

        const int WM_COPYDATA = 0x004A;

        public Form1()
        {
            InitializeComponent();
        }

        protected override void DefWndProc(ref System.Windows.Forms.Message m)
        {
            switch (m.Msg)
            {
            case WM_COPYDATA:
                COPYDATASTRUCT mystr = new COPYDATASTRUCT();
                Type mytype = mystr.GetType();
                mystr = (COPYDATASTRUCT) m.GetLParam(mytype);
                this.textBox1.Text = mystr.lpData;
                break;
            default:
                base.DefWndProc(ref m);
                break;
            }

        }
    }

    public struct COPYDATASTRUCT
    {
        public IntPtr dwData;
        public int cbData;
        [MarshalAs(UnmanagedType.LPStr)]
        public string lpData;
    }
}