确保只有一个应用程序实例 [英] Ensuring only one application instance

问题描述

可能的重复:
创建单实例的正确方法是什么申请?

我有一个 Winforms 应用程序，它通过以下代码启动启动画面:

I have a Winforms app, which launches a splash screen via the following code:

Hide();
        bool done = false;
        // Below is a closure which will work with outer variables.
        ThreadPool.QueueUserWorkItem(x =>
                                  {
                                      using (var splashForm = new SplashScreen())
                                      {
                                          splashForm.Show();
                                          while (!done)
                                              Application.DoEvents();
                                          splashForm.Close();
                                      }
                                  });

        Thread.Sleep(3000);
        done = true;

以上内容位于主窗体的代码隐藏中，并从加载事件处理程序中调用.

The above is in the main form's codebehind and called from the load event handler.

但是，我如何确保一次只加载一个应用程序实例?在主窗体的加载事件处理程序中，我可以检查进程列表是否在系统上(通过 GetProcessesByName(...))，但有没有更好的方法?

However, how can I ensure that only one instance of the application will load at a time? In the load event handler of the main form, I could check if the process list is on the system (via GetProcessesByName(...)), but is there a better method?

使用 .NET 3.5.

Using .NET 3.5.

推荐答案

GetProcessesByName 是检查另一个实例是否正在运行的缓慢方法.最快、最优雅的方法是使用互斥锁:

GetProcessesByName is slow way of checking if another instance is running. The fastest and elegant method is using mutex:

[STAThread]
    static void Main()
    {
        bool result;
        var mutex = new System.Threading.Mutex(true, "UniqueAppId", out result);

        if (!result)
        {
            MessageBox.Show("Another instance is already running.");
            return;
        }

        Application.Run(new Form1());

        GC.KeepAlive(mutex);                // mutex shouldn't be released - important line
    }

另请记住，您提供的代码不是最佳方法.正如在循环中调用 DoEvents() 的评论之一所建议的那样，这不是最好的主意.

Please also bear in mind that the code you presented is not the best approach. As it was advised in one of comments calling DoEvents() in a loop is not the best idea.

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