一、通过系统事件
1、实现如下：
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows.Forms; using System.Threading; using System.Runtime.InteropServices; namespace Example { public class SinglonProgram { #region 字段 //显示的主窗体 private Form mainForm; //线程同步事件 private static EventWaitHandle programWaitHandle; #endregion #region 属性 #endregion #region 构造函数 public SinglonProgram(Form showForm) { this.mainForm = showForm; //注册一个等待WaitHandle的委托 ThreadPool.RegisterWaitForSingleObject(programWaitHandle, (obj, timeOut) => { ShowForm(); }, null, -1, false); } #endregion #region 私有函数 显示窗体、等 /// <summary> /// 显示窗体 /// </summary> private void ShowForm() { //在拥有mainForm窗体的线程上执行无参委托（Action） this.mainForm.Invoke(new Action(() => { this.mainForm.Visible = true; if(this.mainForm.WindowState == FormWindowState.Minimized) { this.mainForm.WindowState = FormWindowState.Normal; } this.mainForm.Show(); bool isForeground = SetForegroundWindow(this.mainForm.Handle); MessageBox.Show(isForeground.ToString()); } )); } #endregion #region 公共函数 只有一个程序运行 /// <summary> /// 是否创建了已命名的系统事件 /// </summary> /// <returns></returns> public static bool isNamedSystemEvent() { bool createdNew; programWaitHandle = new EventWaitHandle(true, EventResetMode.AutoReset, Application.ProductName, out createdNew); return !createdNew; } /// <summary> /// 确保只有一个程序运行 /// </summary> public static void Confirm() { // 如果该命名事件已命名(运行实例已经存在)，则发事件通知并退出 if (isNamedSystemEvent()) { programWaitHandle.Set(); //将事件状态设置为终止状态，允许一个或多个等待线程继续 Environment.Exit(1); } } #endregion #region 接口函数 激活窗体且前端显示等 /// <summary> /// 前端显示且激活窗体 /// </summary> /// <param name="hWnd">窗体句柄</param> /// <returns></returns> [DllImport("user32.dll")] public static extern bool SetForegroundWindow(IntPtr hWnd); #endregion #region 虚函数 #endregion } }
2、调用如下：
static class Program { /// <summary> /// 应用程序的主入口点。 /// </summary> [STAThread] static void Main() { SinglonProgram.Confirm(); Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new frmMain()); } }
二、通过查询线程
具体如下：（测试时发现，不调试和调试区别下会产生两个程序）
using System; using System.Collections.Generic; using System.Linq; using System.Windows.Forms; using System.Runtime.InteropServices; using System.Diagnostics; using System.Reflection; namespace Test { static class Program { /// <summary> /// 该函数设置由不同线程产生的窗口的显示状态。 /// </summary> /// <param name="hWnd">窗口句柄</param> /// <param name="cmdShow">指定窗口如何显示。查看允许值列表，请查阅ShowWlndow函数的说明部分。</param> /// <returns>如果函数原来可见，返回值为非零；如果函数原来被隐藏，返回值为零。</returns> [DllImport("User32.dll")] private static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow); /// <summary> /// 该函数将创建指定窗口的线程设置到前台，并且激活该窗口。键盘输入转向该窗口，并为用户改各种可视的记号。系统给创建前台窗口的线程分配的权限稍高于其他线程。 /// </summary> /// <param name="hWnd">将被激活并被调入前台的窗口句柄。</param> /// <returns>如果窗口设入了前台，返回值为非零；如果窗口未被设入前台，返回值为零。</returns> [DllImport("User32.dll")] private static extern bool SetForegroundWindow(IntPtr hWnd); private const int WS_SHOWNORMAL = 1; /// <summary> /// 应用程序的主入口点。 /// </summary> [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Process instance = RunningInstance(); if (instance == null) { Form1 frm = new Form1(); Application.Run(new Form1()); } else { HandleRunningInstance(instance); } } /// <summary> /// 获取正在运行的实例，没有运行的实例返回null; /// </summary> public static Process RunningInstance() { Process current = Process.GetCurrentProcess(); Process[] processes = Process.GetProcessesByName(current.ProcessName); foreach (Process process in processes) { if (process.Id != current.Id) { if (Assembly.GetExecutingAssembly().Location.Replace("/", "\\") == current.MainModule.FileName) { return process; } } } return null; } /// <summary> /// 显示已运行的程序。 /// </summary> public static void HandleRunningInstance(Process instance) { ShowWindowAsync(instance.MainWindowHandle, WS_SHOWNORMAL); //显示，可以注释掉 SetForegroundWindow(instance.MainWindowHandle); //放到前端 } } }
三、互斥体
/// <summary> /// 应用程序的主入口点。 /// </summary> [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Process instance = RunningInstance(); bool blnIsRunning; Mutex mutexApp = new Mutex(false, Assembly.GetExecutingAssembly().FullName, out blnIsRunning); if (!blnIsRunning) { MessageBox.Show("程序已经运行！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); return; } Application.Run(new Form1()); }
四、额外
public void A() { //=====创建互斥体法：===== bool blnIsRunning; Mutex mutexApp = new Mutex(false, Assembly.GetExecutingAssembly().FullName, out blnIsRunning); if (!blnIsRunning) { MessageBox.Show("程序已经运行！", "提示",MessageBoxButtons.OK, MessageBoxIcon.Exclamation); return; } } public void B() { //保证同时只有一个客户端在运行 System.Threading.Mutex mutexMyapplication = new System.Threading.Mutex(false, "OnePorcess.exe"); if (!mutexMyapplication.WaitOne(100, false)) { MessageBox.Show("程序" + Application.ProductName + "已经运行！", Application.ProductName, MessageBoxButtons.OK, MessageBoxIcon.Error); return; } } public void c() { //=====判断进程法：(修改程序名字后依然能执行)===== Process current = Process.GetCurrentProcess(); Process[] processes = Process.GetProcessesByName(current.ProcessName); foreach (Process process in processes) { if (process.Id != current.Id) { if (process.MainModule.FileName == current.MainModule.FileName) { MessageBox.Show("程序已经运行！", Application.ProductName, MessageBoxButtons.OK, MessageBoxIcon.Exclamation); return; } } } }