How can i do this with the C# 'new Process' object.

Question

Hi folks,

I wish to pass some data to the delegate method, of a Process object, when it fires the Exited event --- i'm not sure how.

---

I've got some code (in a windows service) that is going to take a while .. so i'm forking off a new process to do it .. like ...

string recipientEmail = "[email protected]";

var commandProcess = new Process
{
    StartInfo = 
        {
            FileName = commandLine,
            Arguments = commandArgs
        }
};
commandProcess.Start();

Now, when this finishes, I wish to do some other stuff. For example, send an email.

Now, that's not too hard when we can :-

commandProcess.EnableRaisingEvents = true;

// Method to handle when the process has exited.
commandProcess.Exited += CommandProcess_Exited;

Now, i'm not sure how i pass the variable recipientEmail to the method CommandProcess_Exited when the Exited event is fired.

eg method which the CommandProcess_Exited method will call :-

private static void SendEmailToRecipient(string recipientEmail)
{
    ....
}

Is this possible?

Answer 1

You can either make the variable non-local, that is, declare it in the class so it's visible to your event handling method.

Or you can use a delegate and write the method inline, which allows you to access local variables:

commandProcess.Exited += delegate
    {
         SendEmailToRecipient(recipientEmail);
    };

Answer 2

For something like this what I tend to do is extend the EventArgs class and create my own version which includes the required data:

public class MyProgramEventArgs : EventArgs
{
     public MyProgramEventArgs()
     {
     }

     public string RecipientEmail { get; set; }
}

Then what you can do is capture the Exited from the program itself, do some pre-processing on the args, then invoke the method:

public static void Main(string[] args)
{
    commandProcess.EnableRaisingEvents = true;
    ...
    commandProcess.Exited += OnProgramExited;
}

public void OnProgramExited(object sender, EventArgs e)
{
    MyProgramEventArgs args = new MyProgramEventArgs();
    args.RecipientEmail = "[email protected]";
    CommandProcess_Exited(sender, args);
}

public void CommandProcess_Exited(object sender, MyProgramEventArgs e)
{
    SendEmailToRecipient(e.RecipientEmail);   
}