c#结构化异常处理

class Progran
{
    static string[] eTypes = { "none", "simple", "index", "nested index", "filter" };

    static void Main(string[] args)
    {
        foreach (string type in eTypes)
        {
            try
            {
                Console.WriteLine("Main() try block reached.");
                Console.WriteLine($"ThrowException(\"{type}\") called.");
                ThrowException(type);
                Console.WriteLine("Main() try block continues.");
            }
            catch (System.IndexOutOfRangeException e) when (type == "filter")
            {
                Console.BackgroundColor = ConsoleColor.Red;
                Console.WriteLine("Main() FILTERED System.IndexOutOfRangeException" +
                    $"catch block reached. Message:\n\"{e.Message}\"");
                Console.ResetColor();
            }
            catch (System.IndexOutOfRangeException e)
            {
                Console.WriteLine("Main() System.IndexOutOfRangeException catch " +
                    $"catch block reached. Message:\n\"{e.Message}\"");
            }
            catch
            {
                Console.WriteLine("Main() general catch block reached.");
            }
            finally
            {
                Console.WriteLine("Main() finally block reached.");
            };
        }
    }
    static void ThrowException(string exceptionType)
    {
        Console.WriteLine($"ThrowException(\"{exceptionType}\") reached.");
        switch (exceptionType)
        {
            case "none":
                Console.WriteLine("Not throwing an exception.");
                break;
            case "simple":
                Console.WriteLine("Throwing System.Exception.");
                throw new System.Exception();
            case "index":
                Console.WriteLine("Throwing System.IndexOutOfRangeException.");
                eTypes[5] = "error";
                break;
            case "nested index":
                try
                {
                    Console.WriteLine("ThrowException(\"nested index\") general"
                        + " try block reached.");
                    Console.WriteLine("ThrowException(\"index\") called.");
                    ThrowException("index");
                }
                catch
                {
                    Console.WriteLine("ThrowException(\"nested index\") general" +
                        " catch block reached.");
                    throw;
                }
                finally
                {
                    Console.WriteLine("ThrowException(\"nested index\") finally" +
                        " block reached.");
                }
                break;
            case "filter":
                try
                {
                    Console.WriteLine("ThrowException(\"filter\")" + " try block reached.");
                    Console.WriteLine("ThrowException(\"index\") called.");
                    ThrowException("index");
                }
                catch
                {
                    Console.WriteLine("ThrowException(\"filter\") general" + " catch block reached.");
                    throw;
                }
                break;

        }
    }
}