If another instance is running, [set focus] and open file on the 'old' instance

Question

How can i check if another instance is running ?
Also if it is running how can I force my already opened instance to open a file ?
Also if it is possible can I force it to get focus? ( I need this seperate)

Answer 1

How can i check if another instance is running ?

You could use Process.GetProcesses() to get a list of processes which are running on your machine. And simply do your compare with Process.Name. With rather simple name, you may need additional check for your application.

Also if it is running how can I force my already opened instance to open a file ?

If you want to communicate between 2 processes, I would recommend SendMessage method. See here.

Also if it is possible can I force it to get focus? ( I need this seperate)

You could use SetForgoundWindow method (also require P/Invoke). See here.