Type 'System.Diagnostics.Process' does not contain a definition for 'CloseMainWindow'


I am writing an application in Unity that requires another application to be running. I have been able to successfully start another program from Unity, but I have not been able to close it. I am

 using System.Diagnostics

 Process p = new Process();
 p.StartInfo.FileName = @"C:\path\to\program.exe";
 p.Start();  // works up to this point
 p.CloseMainWindow(); // throws a compiler error

When I try to run this code, I get a compile error:

Type 'System.Diagnostics.Process' does not contain a definition for 'CloseMainWindow' and no extension method 'CloseMainWindow' of type 'System.Diagnostics.Process' could be found (are you missing a using directive or an assembly reference?)

I get a similar error for the Kill() method.

Both the Kill() and CloseMainWindow() methods are suggested by intellisense in the Monodevelop IDE, and documented in the C# .NET

My theory is that Unity has blocked some features of the .NET framework to prevent a Unity process from shutting down other processes. I have tried using System.Reflection to look inside the Process class, but it isn't working for some mysterious reason (this being my first time using reflection in C#).

How can I close this extra process when the user closes Unity?


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asked Dec 22, 2011 at 10:09 PM

JoeProgram gravatar image

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I have not figured out what is going on, but I have figured out a workaround. Replace:



p.GetType().GetMethod( "CloseMainWindow" ).Invoke( p, new object[]{} );

Using reflection shows that CloseMainWindow and Kill are both still defined, so it seems like a Unity-specific compiler issue.

Another gotcha: If the new process steals focus from Unity, Unity will pause its execution and will not run the CloseMainWindow method until you click back on it.

Dec 22, 2011 at 07:08 PM JoeProgram

Hmm, that sounds strange. According to the MonoCompatibility page this method is supported for standalone builds.

The focus problem is related to your runInBackground - setting which can be configured in the Player settings.

If you're sure that it won't compile in Unity you could create a small sample project which reproduces the problem and file a bugreport so the Unity staff know about the problem.

Dec 23, 2011 at 01:22 AM Bunny83

I started to do this process, but then in my debug project CloseMainWindow() worked perfectly. Something must be obscuring the method in my original project.

Dec 23, 2011 at 05:38 PM JoeProgram
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1 answer: sort voted first

It's a million years since this question was asked, but for others (like me) who stumble across this: you are probably not running on a platform that supports these calls, such as the Web Player.

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answered Oct 28 at 09:53 PM

TimK_personal gravatar image


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asked: Dec 22, 2011 at 10:09 PM

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Last Updated: 3 days ago