blocks|key|1756180|text|使用互斥锁。上面的一个使用GetProcessByName的例子有很多注意事项。这里有一篇关于这个主题的好文章：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1756181|http://odetocode.com/Blogs/scott/archive/2004/08/20/401.aspx|offset|length|1756182|[STAThread]
static+void+Main()+
{
+++using(Mutex+mutex+=+new+Mutex(false,+"Global\\"+%2B+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";|code-block|syntax|javascript|1756183|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|1O|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@$D|T|E|U|1|V]]|A|$]]|$1|F|3|G|5|H|7|W|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|C]]]]

Use Mutex. One of the examples above using GetProcessByName has many caveats. Here is a good article on the subject:

<a href="http://odetocode.com/Blogs/scott/archive/2004/08/20/401.aspx" rel="noreferrer">http://odetocode.com/Blogs/scott/archive/2004/08/20/401.aspx</a>

<pre><code>[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";
</code></pre>

blocks|key|1756050|text|if+(Process.GetProcessesByName(Process.GetCurrentProcess().ProcessName).Length+>+1)
{
++AppLog.Write("Application+XXXX+already+running.+Only+one+instance+of+this+application+is+allowed",+AppLog.LogMessageType.Warn);
++return;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1756051|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>if (Process.GetProcessesByName(Process.GetCurrentProcess().ProcessName).Length &gt; 1)
{
 AppLog.Write("Application XXXX already running. Only one instance of this application is allowed", AppLog.LogMessageType.Warn);
 return;
}
</code></pre>

blocks|key|1541297|text|下面是确保只有一个实例在运行所需的代码。这是使用命名互斥锁的方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1541298|public+class+Program
{
++++static+System.Threading.Mutex+singleton+=+new+Mutex(true,+"My+App+Name");

++++static+void+Main(string[]+args)
++++{
++++++++if+(!singleton.WaitOne(TimeSpan.Zero,+true))
++++++++{
++++++++++++//there+is+already+another+instance+running!
++++++++++++Application.Exit();
++++++++}
++++}
}|code-block|syntax|javascript|1541299|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here is the code you need to ensure that only one instance is running. This is the method of using a named mutex. 

<pre><code>public class Program
{
 static System.Threading.Mutex singleton = new Mutex(true, "My App Name");

 static void Main(string[] args)
 {
 if (!singleton.WaitOne(TimeSpan.Zero, true))
 {
 //there is already another instance running!
 Application.Exit();
 }
 }
}
</code></pre>

blocks|key|1755912|text|Hanselman使用来自Microsoft.VisualBasic程序集的WinFormsApplicationBase类a+post来完成此操作。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1755913|entityMap|0|LINK|mutability|MUTABLE|url|http://www.hanselman.com/blog/TheWeeklySourceCode31SingleInstanceWinFormsAndMicrosoftVisualBasicdll.aspx^0|1Q|6|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Hanselman has <a href="http://www.hanselman.com/blog/TheWeeklySourceCode31SingleInstanceWinFormsAndMicrosoftVisualBasicdll.aspx" rel="noreferrer">a post</a> on using the WinFormsApplicationBase class from the Microsoft.VisualBasic assembly to do this.

blocks|key|1756447|text|1-在program.cs+->中创建引用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1756448|using+System.Diagnostics;|code-block|syntax|javascript|1756449|2-作为代码->的第一行放入void+Main()|offset|length|style|CODE|1756450|+if+(Process.GetProcessesByName(Process.GetCurrentProcess().ProcessName).Length+>1)
++++++++++++++++return;|1756451|就这样。|1756452|entityMap^0|0|0|E|B|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

1 - Create a reference in program.cs -> 

<pre><code>using System.Diagnostics;
</code></pre>

2 - Put into <code>void Main()</code> as the first line of code ->

<pre><code> if (Process.GetProcessesByName(Process.GetCurrentProcess().ProcessName).Length &gt;1)
 return;
</code></pre>

That's it.

blocks|key|1756387|text|我在这里尝试了所有的解决方案，但在我的C#+.net+4.0项目中都不起作用。希望能帮助这里的人，解决方案对我很有效：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1756388|作为主类变量：|1756389|private+static+string+appGuid+=+"WRITE+AN+UNIQUE+GUID+HERE";
private+static+Mutex+mutex;|code-block|syntax|javascript|1756390|当您需要检查app是否已经在运行时：|1756391|bool+mutexCreated;
mutex+=+new+Mutex(true,+"Global\\"+%2B+appGuid,+out+mutexCreated);
if+(mutexCreated)
++++mutex.ReleaseMutex();

if+(!mutexCreated)
{
++++//App+is+already+running,+close+this!
++++Environment.Exit(0);+//i+used+this+because+its+a+console+app
}|1756392|我只需要在某些条件下关闭其他实例，这对我的目的很有效。|1756393|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

i tried all the solutions here and nothing worked in my C# .net 4.0 project. Hoping to help someone here the solution that worked for me:

As main class variables:

<pre><code>private static string appGuid = "WRITE AN UNIQUE GUID HERE";
private static Mutex mutex;
</code></pre>

When you need to check if app is already running:

<pre><code>bool mutexCreated;
mutex = new Mutex(true, "Global\\" + appGuid, out mutexCreated);
if (mutexCreated)
 mutex.ReleaseMutex();

if (!mutexCreated)
{
 //App is already running, close this!
 Environment.Exit(0); //i used this because its a console app
}
</code></pre>

I needed to close other istances only with some conditions, this worked well for my purpose

blocks|key|1541202|text|使用Visual+Studio+2005或2008当您为可执行文件创建项目时，在“应用程序”面板内的属性窗口上有一个名为“Make+single+instance+application”的复选框，您可以激活该复选框以将应用程序转换为单实例应用程序。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1541203|下面是我所说的窗口的截图：|1541204|📷|atomic|offset|length|1541205|这是一个Visual+Studio+2008+windows应用程序项目。|1541206|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/1805c1af400b4ff9a12f40f93e89e2f0.png|imageAlt^0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|V|8|@]|9|@$G|W|H|X|1|Y]]|A|$]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R|S|-4]]]]

Using Visual Studio 2005 or 2008 when you create a project for an executable, on the properties windows inside the "Application" panel there is a check box named “Make single instance application” that you can activate to convert the application on a single instance application.

Here is a capture of the window I'm talking of:
<img src="https://i.stack.imgur.com/Wtori.png" alt="enter image description here">
This is a Visual Studio 2008 windows application project.

blocks|key|1540923|text|http://en.csharp-online.net/Application_Architecture_in_Windows_Forms_2.0—Single-Instance_Detection_and_Management|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1540924|entityMap|0|LINK|mutability|MUTABLE|url|http://en.csharp-online.net/Application_Architecture_in_Windows_Forms_2.0^0|0|21|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

<a href="http://en.csharp-online.net/Application_Architecture_in_Windows_Forms_2.0" rel="nofollow noreferrer">http://en.csharp-online.net/Application_Architecture_in_Windows_Forms_2.0</a>—Single-Instance_Detection_and_Management

blocks|key|1541424|text|这是VB.Net的代码|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1541425|Private+Shared+Sub+Main()
++++Using+mutex+As+New+Mutex(False,+appGuid)
++++++++If+Not+mutex.WaitOne(0,+False)+Then
++++++++++++++MessageBox.Show("Instance+already+running",+"ERROR",+MessageBoxButtons.OK,+MessageBoxIcon.Error)
++++++++++++Return
++++++++End+If

++++++++Application.Run(New+Form1())
++++End+Using
End+Sub|code-block|syntax|javascript|1541426|这是C#的代码|1541427|private+static+void+Main()
{
++++using+(Mutex+mutex+=+new+Mutex(false,+appGuid))+{
++++++++if+(!mutex.WaitOne(0,+false))+{
++++++++++++MessageBox.Show("Instance+already+running",+"ERROR",+MessageBoxButtons.OK,+MessageBoxIcon.Error);
++++++++++++return;
++++++++}

++++++++Application.Run(new+Form1());
++++}
}|1541428|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

This is the code for VB.Net

<pre><code>Private Shared Sub Main()
 Using mutex As New Mutex(False, appGuid)
 If Not mutex.WaitOne(0, False) Then
 MessageBox.Show("Instance already running", "ERROR", MessageBoxButtons.OK, MessageBoxIcon.Error)
 Return
 End If

 Application.Run(New Form1())
 End Using
End Sub
</code></pre>

This is the code for C#

<pre><code>private static void Main()
{
 using (Mutex mutex = new Mutex(false, appGuid)) {
 if (!mutex.WaitOne(0, false)) {
 MessageBox.Show("Instance already running", "ERROR", MessageBoxButtons.OK, MessageBoxIcon.Error);
 return;
 }

 Application.Run(new Form1());
 }
}
</code></pre>

blocks|key|1540970|text|本文简单介绍如何创建一个windows应用程序，并控制其实例数或仅运行单个实例。这是业务应用程序的典型需求。已经有很多其他可能的解决方案来控制这种情况。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1540971|https://web.archive.org/web/20090205153420/http://www.openwinforms.com/single_instance_application.html|offset|length|1540972|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|2V|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@$D|O|E|P|1|Q]]|A|$]]|$1|F|3|-4|5|6|7|R|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|C]]]]

This article simply explains how you can create a windows application with control on the number of its instances or run only single instance. This is very typical need of a business application. There are already lots of other possible solutions to control this.
<a href="https://web.archive.org/web/20090205153420/http://www.openwinforms.com/single_instance_application.html" rel="nofollow noreferrer">https://web.archive.org/web/20090205153420/http://www.openwinforms.com/single_instance_application.html</a>

blocks|key|1756271|text|使用VB.NET！不:真的;)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1756272|使用Microsoft.VisualBasic.ApplicationServices；|1756273|来自VB.Net的WindowsFormsApplicationBase为您提供了一个"SingleInstace“属性，该属性确定其他实例并只允许一个实例运行。|1756274|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

Use VB.NET!
No: really ;)

using Microsoft.VisualBasic.ApplicationServices;

The WindowsFormsApplicationBase from VB.Net provides you with a "SingleInstace" Property, which determines other Instances and let only one Instance run.

blocks|key|1541396|text|[STAThread]
static+void+Main()++++++++++++++++++//+args+are+OK+here,+of+course
{
++++bool+ok;
++++m+=+new+System.Threading.Mutex(true,+"YourNameHere",+out+ok);

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

++++Application.Run(new+Form1());+++//+or+whatever+was+there

++++GC.KeepAlive(m);++++++++++++++++//+important!
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1541397|来自：Ensuring+a+single+instance+of+.NET+Application|unstyled|offset|length|1541398|和：Single+Instance+Application+Mutex|1541399|答案与@Smink和@twist相同，但有一点不同：|1541400|Jon+Skeet's+FAQ+on+C#了解为什么GC.KeepAlive很重要|1541401|entityMap|0|LINK|mutability|MUTABLE|url|http://www.ai.uga.edu/mc/SingleInstance.html|1|http://www.codeproject.com/KB/cs/SingleInstanceAppMutex.aspx|2|http://www.yoda.arachsys.com/csharp/faq/|3|http://msdn.microsoft.com/en-us/library/system.gc.keepalive.aspx^0|0|3|1A|0|0|2|X|1|0|0|0|L|2|Q|C|3|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|13|8|@]|9|@$G|14|H|15|1|16]]|A|$]]|$1|I|3|J|5|F|7|17|8|@]|9|@$G|18|H|19|1|1A]]|A|$]]|$1|K|3|L|5|F|7|1B|8|@]|9|@]|A|$]]|$1|M|3|N|5|F|7|1C|8|@]|9|@$G|1D|H|1E|1|1F]|$G|1G|H|1H|1|1I]]|A|$]]|$1|O|3|-4|5|F|7|1J|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]|W|$5|R|S|T|A|$U|X]]|Y|$5|R|S|T|A|$U|Z]]|10|$5|R|S|T|A|$U|11]]]]

<pre><code>[STAThread]
static void Main() // args are OK here, of course
{
 bool ok;
 m = new System.Threading.Mutex(true, "YourNameHere", out ok);

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

 Application.Run(new Form1()); // or whatever was there

 GC.KeepAlive(m); // important!
}
</code></pre>

From: <a href="http://www.ai.uga.edu/mc/SingleInstance.html" rel="nofollow noreferrer">Ensuring a single instance of .NET Application</a>

and: <a href="http://www.codeproject.com/KB/cs/SingleInstanceAppMutex.aspx" rel="nofollow noreferrer">Single Instance Application Mutex</a>

Same answer as @Smink and @Imjustpondering with a twist:

<a href="http://www.yoda.arachsys.com/csharp/faq/" rel="nofollow noreferrer">Jon Skeet's FAQ on C#</a> to find out why <a href="http://msdn.microsoft.com/en-us/library/system.gc.keepalive.aspx" rel="nofollow noreferrer">GC.KeepAlive</a> matters

blocks|key|1541010|text|http://www.codeproject.com/KB/cs/SingleInstancingWithIpc.aspx|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1541011|entityMap|0|LINK|mutability|MUTABLE|url^0|0|1P|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@$A|L|B|M|1|N]]|C|$]]|$1|D|3|-4|5|6|7|O|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|4]]]]

<a href="http://www.codeproject.com/KB/cs/SingleInstancingWithIpc.aspx" rel="nofollow noreferrer">http://www.codeproject.com/KB/cs/SingleInstancingWithIpc.aspx</a>

blocks|key|1755965|text|您必须使用System.Diagnostics.Process。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1755966|查看：http://www.devx.com/tips/Tip/20044|offset|length|1755967|entityMap|0|LINK|mutability|MUTABLE|url|http://www.devx.com/tips/Tip/20044^0|0|3|Y|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

You have to use System.Diagnostics.Process.

Check out: <a href="http://www.devx.com/tips/Tip/20044" rel="nofollow noreferrer">http://www.devx.com/tips/Tip/20044</a>

blocks|key|1541613|text|简单地使用一个StreamWriter，这个怎么样？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1541614|System.IO.File.StreamWriter+OpenFlag+=+null;+++//globally|code-block|syntax|javascript|1541615|和|1541616|try
{
++++OpenFlag+=+new+StreamWriter(Path.GetTempPath()+%2B+"OpenedIfRunning");
}
catch+(System.IO.IOException)+//file+in+use
{
++++Environment.Exit(0);
}|1541617|entityMap^0|7|C|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

Simply using a <code>StreamWriter</code>, how about this?

<pre><code>System.IO.File.StreamWriter OpenFlag = null; //globally
</code></pre>

and

<pre><code>try
{
 OpenFlag = new StreamWriter(Path.GetTempPath() + "OpenedIfRunning");
}
catch (System.IO.IOException) //file in use
{
 Environment.Exit(0);
}
</code></pre>

blocks|key|1541096|text|通常它是通过一个命名互斥锁来完成的(使用新的互斥锁(“你的应用程序名”，true+)并检查返回值)，但是在can+do+it+for+you的Microsoft.VisualBasic.dll中也有一些支持类。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1541097|entityMap|0|LINK|mutability|MUTABLE|url|http://www.hanselman.com/blog/TheWeeklySourceCode31SingleInstanceWinFormsAndMicrosoftVisualBasicdll.aspx^0|1H|H|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Normally it's done with a named Mutex (use new Mutex( "your app name", true ) and check the return value), but there's also some support classes in Microsoft.VisualBasic.dll that <a href="http://www.hanselman.com/blog/TheWeeklySourceCode31SingleInstanceWinFormsAndMicrosoftVisualBasicdll.aspx" rel="nofollow noreferrer">can do it for you</a>.

blocks|key|1541528|text|在纯C#中，这对我很有效。try/catch是当列表中的某个进程可能在循环期间退出时。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1541529|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%2B%2B;++++++++++++++++++++++++
++++++++++++++++++++if(procCount+>+1)+{
+++++++++++++++++++++++Application.Exit();
+++++++++++++++++++++++return;
++++++++++++++++++++}
++++++++++++++++}
++++++++++++}
++++++++++++catch+{+}
++++++++}
++++++++Application.Run(new+Form1());
}|code-block|syntax|javascript|1541530|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This worked for me in pure C#. the try/catch is when possibly a process in the list exits during your loop.

<pre><code>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 &gt; 1) {
 Application.Exit();
 return;
 }
 }
 }
 catch { }
 }
 Application.Run(new Form1());
}
</code></pre>

blocks|key|1541668|text|这些答案对我来说都不起作用，因为我需要使用monodevelop在Linux下工作。这对我来说很有效：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1541669|调用此方法，并向其传递唯一的ID|1541670|++++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+%2B+".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+%2B=+(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);+
++++++++}
++++}+++++++++|code-block|syntax|javascript|1541671|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

None of this answers worked for me because I needed this to work under Linux using monodevelop. This works great for me:

Call this method passing it a unique ID

<pre><code> 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) =&gt;
 {
 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); 
 }
 } 
</code></pre>

In .NET, what's the best way to prevent multiple instances of an app from running at the same time? And if there's no "best" technique, what are some of the caveats to consider with each solution?

Prevent multiple instances of a given app in .NET?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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在.NET中，防止应用程序的多个实例同时运行的最佳方式是什么？如果没有“最佳”技术，那么对于每种解决方案都需要考虑哪些注意事项？

问是否在.NET中阻止给定应用程序的多个实例？
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