在。net下使用c#和WPF(而不是Windows窗体或控制台),创建一个只能作为单个实例运行的应用程序的正确方法是什么?
我知道它与某种叫做互斥的神秘事物有关,我很少能找到有人费心停下来解释其中一个是什么。
代码还需要通知已经运行的实例,用户试图启动第二个实例,如果存在命令行参数,还可能传递任何命令行参数。
在。net下使用c#和WPF(而不是Windows窗体或控制台),创建一个只能作为单个实例运行的应用程序的正确方法是什么?
我知道它与某种叫做互斥的神秘事物有关,我很少能找到有人费心停下来解释其中一个是什么。
代码还需要通知已经运行的实例,用户试图启动第二个实例,如果存在命令行参数,还可能传递任何命令行参数。
当前回答
请看下面的代码。它是防止一个WPF应用程序有多个实例的一个很好的简单解决方案。
private void Application_Startup(object sender, StartupEventArgs e)
{
Process thisProc = Process.GetCurrentProcess();
if (Process.GetProcessesByName(thisProc.ProcessName).Length > 1)
{
MessageBox.Show("Application running");
Application.Current.Shutdown();
return;
}
var wLogin = new LoginWindow();
if (wLogin.ShowDialog() == true)
{
var wMain = new Main();
wMain.WindowState = WindowState.Maximized;
wMain.Show();
}
else
{
Application.Current.Shutdown();
}
}
其他回答
看起来有一个很好的方法来处理这个问题:
WPF单实例应用程序
这提供了一个类,您可以添加它来管理所有互斥量和消息传递的cruff,从而将实现简化到非常简单的程度。
基于命名互斥的方法不是跨平台的,因为命名互斥在Mono中不是全局的。基于进程枚举的方法没有任何同步,可能会导致不正确的行为(例如,同时启动的多个进程可能都根据时间自行终止)。在控制台应用程序中不需要基于windows系统的方法。这个解决方案建立在Divin的答案之上,解决了所有这些问题:
using System;
using System.IO;
namespace TestCs
{
public class Program
{
// The app id must be unique. Generate a new guid for your application.
public static string AppId = "01234567-89ab-cdef-0123-456789abcdef";
// The stream is stored globally to ensure that it won't be disposed before the application terminates.
public static FileStream UniqueInstanceStream;
public static int Main(string[] args)
{
EnsureUniqueInstance();
// Your code here.
return 0;
}
private static void EnsureUniqueInstance()
{
// Note: If you want the check to be per-user, use Environment.SpecialFolder.ApplicationData instead.
string lockDir = Path.Combine(
Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData),
"UniqueInstanceApps");
string lockPath = Path.Combine(lockDir, $"{AppId}.unique");
Directory.CreateDirectory(lockDir);
try
{
// Create the file with exclusive write access. If this fails, then another process is executing.
UniqueInstanceStream = File.Open(lockPath, FileMode.Create, FileAccess.Write, FileShare.None);
// Although only the line above should be sufficient, when debugging with a vshost on Visual Studio
// (that acts as a proxy), the IO exception isn't passed to the application before a Write is executed.
UniqueInstanceStream.Write(new byte[] { 0 }, 0, 1);
UniqueInstanceStream.Flush();
}
catch
{
throw new Exception("Another instance of the application is already running.");
}
}
}
}
简单地使用一个StreamWriter,怎么样?
System.IO.File.StreamWriter OpenFlag = null; //globally
and
try
{
OpenFlag = new StreamWriter(Path.GetTempPath() + "OpenedIfRunning");
}
catch (System.IO.IOException) //file in use
{
Environment.Exit(0);
}
这里有一个解决方案:
Protected Overrides Sub OnStartup(e As StartupEventArgs)
Const appName As String = "TestApp"
Dim createdNew As Boolean
_mutex = New Mutex(True, appName, createdNew)
If Not createdNew Then
'app is already running! Exiting the application
MessageBox.Show("Application is already running.")
Application.Current.Shutdown()
End If
MyBase.OnStartup(e)
End Sub
一个节省时间的c# Winforms解决方案…
Program.cs:
using System;
using System.Windows.Forms;
// needs reference to Microsoft.VisualBasic
using Microsoft.VisualBasic.ApplicationServices;
namespace YourNamespace
{
public class SingleInstanceController : WindowsFormsApplicationBase
{
public SingleInstanceController()
{
this.IsSingleInstance = true;
}
protected override void OnStartupNextInstance(StartupNextInstanceEventArgs e)
{
e.BringToForeground = true;
base.OnStartupNextInstance(e);
}
protected override void OnCreateMainForm()
{
this.MainForm = new Form1();
}
}
static class Program
{
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
string[] args = Environment.GetCommandLineArgs();
SingleInstanceController controller = new SingleInstanceController();
controller.Run(args);
}
}
}