此範例示範如何在兩個執行檔中使用SendMessage傳送值與接收值
此範例是傳遞int數字，如何傳遞string字串就給大家當做練習題了
以下這些程式碼是宣告會用到的API
[DllImport("user32.dll")]
static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, UIntPtr
wParam, IntPtr lParam);
[DllImport("user32.dll")]
private static extern int SendMessage(IntPtr hwnd, uint wMsg, int wParam, IntPtr lParam);
[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
static extern uint RegisterWindowMessage(string lpString);
uint MSG_SHOW = RegisterWindowMessage("Show Message");
[DllImport("user32.dll")]
static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

IntPtr nPrt = FindWindow(null, "TestB");//找TestB的IntPtr 用來代表指標或控制代碼
http://msdn.microsoft.com/query/dev10.query?appId=Dev10IDEF1&l=ZH-TW&k=k%28SYSTEM.INTPTR%29;k%28INTPTR%29;k%28TargetFrameworkMoniker-%22.NETFRAMEWORK%2cVERSION%3dV3.5%22%29;k%28DevLang-CSHARP%29&rd=true
SendMessage(nPrt, MSG_SHOW, iNum, IntPtr.Zero);
這行就是把數字傳送到目標視窗TestB
以下是TestA的完整程式碼

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

using System.Runtime.InteropServices;
namespace TestA
{
    public partial class Form1 : Form
    {
        [DllImport("user32.dll")]
        static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, UIntPtr
        wParam, IntPtr lParam);
        [DllImport("user32.dll")]
        private static extern int SendMessage(IntPtr hwnd, uint wMsg, int wParam, IntPtr lParam);
        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern uint RegisterWindowMessage(string lpString);
        uint MSG_SHOW = RegisterWindowMessage("Show Message");
        [DllImport("user32.dll")]
        static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            IntPtr nPrt = FindWindow(null, "TestB");//找TestB的IntPtr 用來代表指標或控制代碼
            if (nPrt != IntPtr.Zero && textBox1.Text.Trim()!="" )
            {
                try
                {
                    string tempWord = textBox1.Text.Trim();
                    int iNum = int.Parse(tempWord);//把tempWord字串 轉為int,所以值不是數字會變例外
                    SendMessage(nPrt, MSG_SHOW, iNum, IntPtr.Zero); 
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.ToString());   
                }
            } 
        }
    }
}

以下是TestB的完整程式碼

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace TestB
{
    public partial class Form1 : Form
    {
        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern uint RegisterWindowMessage(string lpString); 
        uint MSG_SHOW = RegisterWindowMessage("Show Message");
        public Form1()
        {
            InitializeComponent();
        }
        protected override void WndProc(ref Message m)
        {
            if (m.Msg == MSG_SHOW)
            {
                label1.Text = (string) m.WParam.ToString();              
            }
            base.WndProc(ref m);
        }
    }
}

全系列文章列表