Comments on: Single instance applications in Windows CE

By: domingo

domingo — Fri, 09 Jul 2010 21:41:51 +0000

I work in VB for Windows Mobile. I translated your code and this is what I have:
Dim Sistema As uso
Dim System.Windows.Forms As uso
Dim System.Runtime.InteropServices As uso
Dim System.Reflection As uso
Dim de As espacioDim Bitmatic As nombres
Dim clase As estáticoDim
( DllImport (” coredll.dll “, SetLastError = verdadero)) público estático externo CreateMutex IntPtr ( IntPtr Attr , bool Propios, cadena Nombre )
( DllImport (” coredll.dll “, SetLastError = verdadero)) público estático externo bool ReleaseMutex ( hMutex IntPtr )
Const ERROR_ALREADY_EXISTS As largo = 183
Function estático(Formulario As frm) As públicoEjecutar As vacío
Dim name As cadena = Assembly.GetExecutingAssembly (). getName () . Nombre
Dim mutexHandle As IntPtr = CreateMutex ( IntPtr.Zero , verdadero, Nombre)
Dim error As largo = Marshal.GetLastWin32Error ()
Dim (Error As siDim ERROR_ALREADY_EXISTS As Not = ) Application.Run (frm )
ReleaseMutex ( mutexHandle )

End Function
************************************************
It does not work. Please can you tell me am I doing wrong?

By: Alden

Alden — Mon, 24 May 2010 12:25:06 +0000

It works perfect.Thanks a lot!

By: Bruce

Bruce — Wed, 19 May 2010 15:29:41 +0000

This worked great! Thanks.

Do you know of a way to set focus back to the running app instead of just exiting (if the application is minimized for example).

By: Mary

Mary — Thu, 06 May 2010 09:45:19 +0000

Very useful. I am going to try this now. IF there is any problem, I will contact you.

By: Will

Will — Fri, 12 Mar 2010 13:37:17 +0000

I was heading down the route of adding and deleting values to the Win32 API atom table and checking all references for any atoms that exist are still running. This is a much simpler and more elegant solution!

Saved me a lot of time, thanks!

By: Jakob

Jakob — Thu, 03 Sep 2009 10:21:27 +0000

Hi Jan,

The creation of the mutex is thread-safe.

Also, according to Microsoft:
“The system closes the handle automatically when the process terminates. The mutex object is destroyed when its last handle has been closed.”
This means that abnormal program termination should release the mutex.

By: Jan

Jan — Thu, 03 Sep 2009 10:05:54 +0000

The solution do not have any concurrency problem, if the creation of the mutex is thread safe.

It is also a smart solution, if the mutex is destroyed, when the single instance application exits abnormally.

Regards
JRO

By: Moose

Moose — Wed, 19 Aug 2009 23:18:41 +0000

Much needed. Thanks!

By: Jakob

Jakob — Thu, 23 Jul 2009 18:29:04 +0000

That is a very good question Pete.

I guess you could use FindWindow and SetForegroundWindow to do it, but I don’t have any code available that does it.

Maybe this should be the subject of my next blog post

By: Pete

Pete — Thu, 23 Jul 2009 15:01:09 +0000

This worked great! Thanks.

Do you know of a way to set focus back to the running app instead of just exiting (if the application is minimized for example).