如何确保有一个应用程序实例正在运行

Question

我想检查用户双击应用程序图标的时间,该应用程序的另一个实例尚未运行.

我读到了My.Application,但我仍然不知道该怎么做.

Answer 1

这是我用过的东西......(.NET 2.0上的C#)

    [STAThread]
    private static void Main(string[] args)
    {
        //this follows best practices on
        //ensuring that this is a single instance app.
        string mutexName = "e50cf829-f6b9-471e-8d9f-67eac3699f09";
        bool grantedOwnership;
        //we prefix the mutexName with "Local\\" to allow this to run under terminal services.
        //The "Local\\" prefix forces this into local user space.
        //If we want to forbid this in TS, use the "Global\\" prefix.
        Mutex singleInstanceMutex = new Mutex(true, "Global\\" + mutexName, out grantedOwnership);
        try
        {
            if (!grantedOwnership)
            {
                MessageBox.Show("Error: X is already running.\n\nYou can only run one copy of X at a time.", "X", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1);
                Application.Exit();
            }
            else
            {
                Application.Run(new X(args));
            }
        }
        finally
        {
            singleInstanceMutex.Close();
        }
    }

Answer 2

在VB .NET中,有一个IsSingleInstance布尔属性可以为您完成工作.

在VB中(取自此处):

Public Class Program
        Inherits Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase

       Public Sub New()
            Me.IsSingleInstance = True
        End Sub



End Class

以下是您在C#中使用它的方法(取自此处):

// SingleInstanceApplication.cs
class SingleInstanceApplication : WindowsFormsApplicationBase {

 // Must call base constructor to ensure correct initial 
 // WindowsFormsApplicationBase configuration
 public SingleInstanceApplication() {

  // This ensures the underlying single-SDI framework is employed, 
  // and OnStartupNextInstance is fired
  this.IsSingleInstance = true;
 }
}


// Program.cs
static class Program {
 [STAThread]
 static void Main(string[] args) {
  Application.EnableVisualStyles();
  SingleInstanceApplication application = 
   new SingleInstanceApplication();
  application.Run(args);
 }
}

确保在项目中引用Microsoft.VisualBasic.dll.

Answer 3

执行此操作的最常见模式是使用单例模式。由于您没有指定一种语言，我将假设您在这里指的是 C# - 如果不是，则大多数 OO 语言的原理仍然相同。

这篇文章应该会给你一些帮助。