How to open the already running application

[aagarwal8@gmail.com]

Hi,

I have a windows form application, where the requirement is as
follows...

If the application is already running, and the user tries to open
another instance of the application, the already running instance of
the application should be activated.

Also my application can be in the system tray (and not be present in
the taskbar), so even in this condition the application should be
activated (i.e. application's main screen should be displayed)

Any help in this regard is appreciated.


Regards,
Ankit!

[Ignacio Machin ( .NET/ C# MVP )]

Re: How to open the already running application

On May 30, 9:10 am, aagarw...@gmail .com wrote:

Hi,
>
I have a windows form application, where the requirement is as
follows...
>
If the application is already running, and the user tries to open
another instance of the application, the already running instance of
the application should be activated.
>
Also my application can be in the system tray (and not be present in
the taskbar), so even in this condition the application should be
activated (i.e. application's main screen should be displayed)
>
Any help in this regard is appreciated.
>
Regards,
Ankit!

Hi,

You have to use something to detect that the app is running already,
take a look at Mutex
To activate the prev. instance you have to get the hWnd of it and make
it the foremost window. Look in the archive of this NG as this is a
recurrent question

[Peter Duniho]

Re: How to open the already running application

On Fri, 30 May 2008 06:10:49 -0700, <aagarwal8@gmai l.comwrote:

I have a windows form application, where the requirement is as
follows...
>
If the application is already running, and the user tries to open
another instance of the application, the already running instance of
the application should be activated.
>
Also my application can be in the system tray (and not be present in
the taskbar), so even in this condition the application should be
activated (i.e. application's main screen should be displayed)

As Ignacio says, you can use a named Mutex to detect the case. As for how
to actually perform the activation, AFAIK there's nothing in .NET that
allows you to do this. You'll need to use p/invoke with the
SetForegroundWi ndow() function, and of course that means you'll have to
actually find the correct window, also via p/invoke (again, AFAIK there's
nothing in .NET to allow you to enumerate top-level windows from other
processes).

There are restrictions on whether your own process will be allowed to
bring the other window to the foreground. When it can't, the window entry
in the task bar will flash instead, which is correct behavior. However,
most likely the new instance of the application will be the foreground
task and will have the rights to bring the other application to the
foreground, so I think that normally this will do exactly what you want.

Pete

[aagarwal8@gmail.com]

Re: How to open the already running application

thanks for the inputs Michael...

However, i was looking forward to an IPC solution. Any leads in that
regard?

Ankit!!

[Peter Duniho]

Re: How to open the already running application

On Sun, 01 Jun 2008 20:59:53 -0700, <aagarwal8@gmai l.comwrote:

thanks for the inputs Michael...
>
However, i was looking forward to an IPC solution. Any leads in that
regard?

In .NET, network i/o (e.g. Socket, UdpClient, TcpClient) is the usual
solution. I have read comments that said they added named pipes to .NET
in the latest version, but I haven't looked into that. Named pipes can be
slightly more convenient, but either approach should work fine.

Keep in mind that using IPC, you're probably anticipating the application
in question trying to restore itself. As I mentioned before, there are
strict rules about when an application can actually be forced to the
foreground. Those rules generally preclude an application forcing itself
to the foreground. If that's important to you, you are actually likely to
be better off having the current foreground application (the newly-started
instance of the same application) handle bringing the other to the
foreground.

Pete

[mpetrotta@gmail.com]

Re: How to open the already running application

On Jun 1, 8:59 pm, aagarw...@gmail .com wrote:

thanks for the inputs Michael...
>
However, i was looking forward to an IPC solution. Any leads in that
regard?

Look at the MSDN remoting documentation to get started:

http://msdn.microsoft.com/en-us/library/72x4h507(VS.80).aspx

Peter mentioned the possibility of using network channels rather than
named pipes. This page addresses that choice:

http://msdn.microsoft.com/en-us/library/4b3scst2(VS.80).aspx

Michael