using System;

using System.Collections.Generic;

using System.Linq;

​

public static class Program

{

    // Provider that raises an exception will be aborted even if the exception is raised

    // you can only circumvent this by handling the exception in the provider

    static IEnumerable<int> TestCases3(Action<int, Exception> exceptionHandler = null)

    {

        foreach (var item in Enumerable.Range(0, 10))

        {

            int value = default(int);

            try

            {

                switch (item)

                {

                    case 2:

                    case 5:

                        throw new ApplicationException("This bit failed");

                    default:

                        value = item;

                        break;

                }

            }

            catch (Exception e)

            {

                if (exceptionHandler != null)

                {

                    exceptionHandler(item, e);

                    continue;

                }

                else

                    throw; // this throw will abort the foreach, after this error there will not be any more values emitted.

            }

​

            yield return value;

        }

    }

​

    public static IEnumerable<T> CatchExceptions<T>(this IEnumerable<T> src, Action<Exception> action = null)

    {

        using (var enumerator = src.GetEnumerator())

        {

            bool next = true;

            while (next)

            {

                try

                {

                    next = enumerator.MoveNext();

                }

                catch (Exception ex)

                {

                    if (action != null)

                    {

                        action(ex);

                    }

​

                    continue;

                }

​

                if (next)

                {

                    yield return enumerator.Current;

                }

            }

        }

    }

​

    public static void Main()

    {

        Console.WriteLine(string.Join(", ", Enumerable.Range(-1, 10).Select(v => 1 / v).CatchExceptions().ToArray()));

        // Test Case 3 highlights how the Exception cannot be caught and execution continue if the exception occurs in the provider source in a way that prevents the iterator from continuing

        Console.WriteLine(string.Join(", ", TestCases3().Select(v => 1 / v).CatchExceptions().ToArray()));

        Console.WriteLine(string.Join(", ", TestCases3().CatchExceptions((e) => Console.WriteLine("Caught: {0}", e.Message)).ToArray()));

        Console.WriteLine(string.Join(", ", TestCases3((i, e) => Console.WriteLine("Handled: {0}", e.Message)).CatchExceptions((e) => Console.WriteLine("Caught: {0}", e.Message)).ToArray()));

        // Demonstrates that CatchExceptions handles all downstream operations that might fail, as long as they do not occur in the enumeration provider.

        Console.WriteLine(string.Join(", ", Enumerable.Range(-1, 10).Select(x =>

            {

                if (x % 2 == 1)

                    throw new ApplicationException("Odd Numbers not allowed");

                return x;

            }

        ).Select(v => 1 / v).CatchExceptions().ToArray()));

    }

}