using System;

public class Program

{

    public static void Main()

    {

        int a = 7;

        int b = 0;

        try

        {

            DoSomethingThatMightFail();

        }

        catch (Exception ex) when (a / b == 0)

        {

            // This block is never reached because a / b throws an ignored

            // DivideByZeroException which is treated as false.

            Console.WriteLine("block 1");

        }

        catch (Exception ex)

        {

            // This block is reached since the DivideByZeroException in the 

            // previous when clause is ignored.

            Console.WriteLine("block 2");

        }

    }

​

    public static void DoSomethingThatMightFail()

    {

        // This will always throw an ArgumentNullException.

        Type.GetType(null);

    }

}