using System;

using System.Threading.Tasks;

​

public class Example

{

   public static void Main()

   {

      var task1 = Task.Run( () => { throw new CustomException("This exception is expected!"); } );

​

      try {

          task1.Wait();

      }

      catch (AggregateException ae)

      {

         // Call the Handle method to handle the custom exception,

         // otherwise rethrow the exception.

          Console.WriteLine($"ErrorMessage={ae.Message + Environment.NewLine}" +

                    $"ErrorStackTrace={ae.StackTrace + Environment.NewLine}" +

                    $"Error InnerException StackTrace={ae?.InnerException?.StackTrace + Environment.NewLine}"); 

         ae.Handle(ex => { if (ex is CustomException)

                             Console.WriteLine(ex.Message);

                          return ex is CustomException;

                        });

      }

   }

}

​

public class CustomException : Exception

{

   public CustomException(String message) : base(message)

   {}

}