C# 如何阻止给一个程序开启多个实例？

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wx6156f59b48086 2021-11-29 17:44:53

文章标签 c# 项目实战作用域推送 linux 文章分类 运维

咨询区

C. Dragon 76：

在 .NET 中是否有比较好的方法可以阻止一个 application 被同时开启了多个实例？如果没有好的办法，那么只能退其次，给每个 application 配一些操作规范。

回答区

ImJustPondering：

我总结有两种解法。

使用 Meutx。

[STAThread]
static void Main() 
{
   using(Mutex mutex = new Mutex(false, "Global\\" + appGuid))
   {
      if(!mutex.WaitOne(0, false))
      {
         MessageBox.Show("Instance already running");
         return;
      }

      Application.Run(new Form1());
   }
}

private static string appGuid = "c0a76b5a-12ab-45c5-b9d9-d693faa6e7b9";

关于 Mutex 更多资料，可参考：http://odetocode.com/Blogs/scott/archive/2004/08/20/401.aspx

使用 Process

可以迭代进程列表，判断是否已经存在该进程名即可，参考如下代码：


using System.Diagnostics;
....
[STAThread]
static void Main()
{
...
        int procCount = 0;
        foreach (Process pp in Process.GetProcesses())
        {
            try
            {
                if (String.Compare(pp.MainModule.FileName, Application.ExecutablePath, true) == 0)
                {
                    procCount++;                        
                    if(procCount > 1) {
                       Application.Exit();
                       return;
                    }
                }
            }
            catch { }
        }
        Application.Run(new Form1());
}

Tono Nam：

其实可以仿 linux 上生成进程文件的方式，所以要做的就是在程序启动后，在某一个文件中写入一个默认的 uniqueid 值，参考如下代码：

  public static void PreventMultipleInstance(string applicationId)
    {
        // Under Windows this is:
        //      C:\Users\SomeUser\AppData\Local\Temp\ 
        // Linux this is:
        //      /tmp/
        var temporaryDirectory = Path.GetTempPath();

        // Application ID (Make sure this guid is different accross your different applications!
        var applicationGuid = applicationId + ".process-lock";

        // file that will serve as our lock
        var fileFulePath = Path.Combine(temporaryDirectory, applicationGuid);

        try
        {
            // Prevents other processes from reading from or writing to this file
            var _InstanceLock = new FileStream(fileFulePath, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None);
            _InstanceLock.Lock(0, 0);
            MonoApp.Logger.LogToDisk(LogType.Notification, "04ZH-EQP0", "Aquired Lock", fileFulePath);

            // todo investigate why we need a reference to file stream. Without this GC releases the lock!
            System.Timers.Timer t = new System.Timers.Timer()
            {
                Interval = 500000,
                Enabled = true,
            };
            t.Elapsed += (a, b) =>
            {
                try
                {
                    _InstanceLock.Lock(0, 0);
                }
                catch
                {
                    MonoApp.Logger.Log(LogType.Error, "AOI7-QMCT", "Unable to lock file");
                }
            };
            t.Start();

        }
        catch
        {
            // Terminate application because another instance with this ID is running
            Environment.Exit(102534); 
        }
    }