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
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);
}
其他回答
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
基于Matt Davis的答案,为方便起见包装成一个类。
public static class SingleAppInstanceChecker
{
/// <summary>
/// Arbitrary unique string
/// </summary>
private static Mutex _mutex = new Mutex(true, "0d12ad74-026f-40c3-bdae-e178ddee8602");
public static bool IsNotRunning()
{
return _mutex.WaitOne(TimeSpan.Zero, true);
}
}
使用示例:
private void Application_Startup(object sender, StartupEventArgs e)
{
if (!SingleAppInstanceChecker.IsNotRunning())
{
MessageBox.Show("Application is already running.");
// Exit application using:
// Environment.Exit(1);
// Application.Current.Shutdown();
// Etc...
return;
}
// Allow startup and continue with normal processing
// ...
}
这是通过事件实现的相同的事情。
public enum ApplicationSingleInstanceMode
{
CurrentUserSession,
AllSessionsOfCurrentUser,
Pc
}
public class ApplicationSingleInstancePerUser: IDisposable
{
private readonly EventWaitHandle _event;
/// <summary>
/// Shows if the current instance of ghost is the first
/// </summary>
public bool FirstInstance { get; private set; }
/// <summary>
/// Initializes
/// </summary>
/// <param name="applicationName">The application name</param>
/// <param name="mode">The single mode</param>
public ApplicationSingleInstancePerUser(string applicationName, ApplicationSingleInstanceMode mode = ApplicationSingleInstanceMode.CurrentUserSession)
{
string name;
if (mode == ApplicationSingleInstanceMode.CurrentUserSession)
name = $"Local\\{applicationName}";
else if (mode == ApplicationSingleInstanceMode.AllSessionsOfCurrentUser)
name = $"Global\\{applicationName}{Environment.UserDomainName}";
else
name = $"Global\\{applicationName}";
try
{
bool created;
_event = new EventWaitHandle(false, EventResetMode.ManualReset, name, out created);
FirstInstance = created;
}
catch
{
}
}
public void Dispose()
{
_event.Dispose();
}
}
这么简单的问题有这么多答案。稍微改变一下这里是我对这个问题的解决方案。
Creating a Mutex can be troublesome because the JIT-er only sees you using it for a small portion of your code and wants to mark it as ready for garbage collection. It pretty much wants to out-smart you thinking you are not going to be using that Mutex for that long. In reality you want to hang onto this Mutex for as long as your application is running. The best way to tell the garbage collector to leave you Mutex alone is to tell it to keep it alive though out the different generations of garage collection. Example:
var m = new Mutex(...);
...
GC.KeepAlive(m);
我从这个网页上获得了灵感:http://www.ai.uga.edu/~mc/SingleInstance.html
我在解决方案中使用互斥来防止多个实例。
static Mutex mutex = null;
//A string that is the name of the mutex
string mutexName = @"Global\test";
//Prevent Multiple Instances of Application
bool onlyInstance = false;
mutex = new Mutex(true, mutexName, out onlyInstance);
if (!onlyInstance)
{
MessageBox.Show("You are already running this application in your system.", "Already Running..", MessageBoxButton.OK);
Application.Current.Shutdown();
}