Application having single instance and multiple instance behaviour

Question

I have created a single instance application using VisualBasic.dll but there are some situations where I need to create multiple instances. I needed single instance behavior to handle the context menu behavior where each windows context menu command will invoke a new instance of the application. I still need some context menus to load a another instance. I solved this by creating a new application context and running it on a new thread.

Sample code

var thread = new Thread(() => ThreadOpenFile(args));
thread.TrySetApartmentState(ApartmentState.STA);
thread.Start();

Thread content

private static void ThreadOpenFile(string[] args)
{
  ApplicationContext appCnxt= new ApplicationContext(new newForm(args[1]));
  Application.Run(appCnxt);            
}

I its same as

private static void ThreadOpenFile(string[] args)
{
  Application.Run(new newForm(args[1]));            
}

This will create a new ApplicationContext, ThreadContext and the new form and Application.Run will link ThreadContext to the ApplicationContext just like starting a new application. I cannot find any documentation explaining what happens and who is managing this "new Thread" I am creating. If I try to start a new process it will invoke single instance handler

protected override void OnStartupNextInstance(StartupNextInstanceEventArgs eventArgs)

of VisualBasic.dll and go in a recursive loop forever as expected. I want to know whether this is the right approach or is there a better way ?

This link shows how to use application context to hook a Splash screen behavior. If there are good references I can find the internals is also appreciated.

Answer 1

Accepting the answer by @HansPassant on comments.

You'll forget Application.EnableVisualStyles() and Application.SetUnhandledExceptionMode(). Like you did. And you're apt to invoke the horrors of getting the SystemEvents class to fire its events on the wrong thread, excessively hard to diagnose. Letting the app start but wait on the 1st process is rather a bad idea. What if the user starts it a 3rd or 4th time? Or nth time