Bdtjtk

For some reason within my console application I cannot get my finally block to run. I was writing this code to test how the finally block works so it is very simple:

static void Main()

{

    int i = 0;

    try

    {

        int j = 1 / i; // Generate a divide by 0 exception.

    }

    finally

    {



        Console.Out.WriteLine("Finished");

        Console.In.ReadLine();

    }

}

At first I had the problem described here but then I tried to run the program outside Visual Studio I got a "Program has stopped responding" error.

Because you do not have a top level exception handler, the .Net runtime is catching the exception for you and aborting the program before the finally has a chance to run. This illustrates the point:

static void Main() 

{

  try

  {

      int i = 0;

      try

      {

         int j = 1 / i; // Generate a divide by 0 exception.

      }

      finally

      {

          Console.Out.WriteLine("Finished");

          Console.In.ReadLine();     

      }

  }

  catch (Exception ex)

  {

      Console.WriteLine(ex.ToString());

  }

}

With this code, the exception is now handled a try...catch higher up in the calling chain (it just happens to be in the same method), so the embedded finally will be executed. The catch need not be in the same function where the exception is being raised, it can be anywhere in the calling chain.

Edit: initially it may seem uncertain when and where an exception will be caught by your program. But think about the boundaries of your application, where the outside world interacts with your code - normally they are limited and well defined. So for a console application, the boundary is the Main method, and this is where you can put the top level exception handler. For a Web forms application, the boundary includes things like button click events (the user is interacting with your UI), so you could have exception handlers in there too. For a class library the boundary is generally the boundary of the application that calls the library, not the library itself. So do not catch exceptions in the library (unless you can sensibly recover from them), but let them bubble up to the calling application instead.

In a larger program this would not be a problem as the DevideByZero exception would "bubble-up" and would hopefully be dealt with somewhere else. Because this is in the main method, the exception has no where to go. This causes the problem you see...

So the following would do as you expect

static void Main(string args)

{

    try

    {

        CatchTest();

    }

    catch (Exception)

    {



    }

}



private static void CatchTest()

{

    int i = 0;

    try

    {

        int j = 1 / i; // Generate a divide by 0 exception.    

    }

    finally

    {

        Console.Out.WriteLine("Finished");

        Console.In.ReadLine();

    }

}

I hope this helps.

You still need a catch to capture the exception throwing:

int i = 0;

        try

        {

            int j = 1 / i; // Generate a divide by 0 exception.

        }

        catch(Exception e)

        {

            Console.Out.WriteLine("Exception caught");

        }

        finally

        {



            Console.Out.WriteLine("Finished");

            Console.In.ReadLine();

        }

This exception is causing the application to crash, and the exception is unhandled therefore terminating the application.

http://msdn.microsoft.com/en-us/library/zwc8s4fz(v=vs.100).aspx

Usually, when an unhandled exception ends an application, whether or not the finally block is run is not important. However, if you have statements in a finally block that must be run even in that situation, one solution is to add a catch block to the try-finally statement.

You need to detach the debugger (e.g. run your application in Release mode), see the following (related) question for more details: finally doesn't seem to execute in C# console application while using F5