Question

Question 1 – practical

I run child process in my C# application using System.Diagnostics.Process. Like the following:

Process process = new Process();

// ... StartInfo initialization here

int timelimit_ms = 30000;
process.Start();
if (!process.WaitForExit(timelimit_ms))
{
  // What exception to throw here?
  throw new Excpetion(
    "An executing method exceeded the time limit of " + timelimit_ms.ToString() + "ms");
}

I’m currently throwing System.ComponentModel.Win32Exception. But I don’t sure it is the best choice. The child process is a simple command line utility. So the first question, what exception to throw in this situation?

Question 2 – thoretical

This is not the first time I ask myself about what exception to throw. And I don’t know of a simple guidelines on how to pick a certain one. There are so much exceptions in C#, deeply inherited from one namespace to another. The second question, how to decide what exception to throw in a specific situation?

Answer 1

Practically, I’d throw a TimeoutException as it describes what is happening

Theoretically, if a quick google / read of the docs doesn’t throw up an exception that already describes what is happening then you can just extend Exception to generate a WeirdThingThatHappensSometimesInMyApplication Exception.

But it depends who or what is going to “read” your exception. If your exception isn’t exceptional then maybe you should do things differently 🙂