Demo-AsyncException

gistfile1.cs

using System;
using System.Threading.Tasks;

namespace dcomartin.Demo.AsyncAwaitExceptions
{
    class Program
    {
        static void Main(string[] args)
        {
            // Since main entry does not support async, lets create a async task.
            Task.Run(async () => 
            {
                var demo = new AsyncDemo();
                
                // Exception thrown will be swallowed
                demo.MethodCalledWithoutAwait();

                // Exception will be raised
                await demo.MethodCalledWithAwait();
            }).Wait();
        }
    }

    public class AsyncDemo
    {

        public void MethodCalledWithoutAwait()
        {
            // Although this method throws an exception, because we are not awaiting it,
            // it will be swallowed and will not be caught.
            AsyncMethodException();
        }

        public async Task MethodCalledWithAwait()
        {
            // Because we are awaiting the async method, the exception thrown will be raised.
            await AsyncMethodException();
        }

        public async Task AsyncMethodException()
        {
            // This method would do some async call (possible IO).
            // For the example, we will throw an exception to show as an example how\
            // the exception will be swollowed by not calling await. 
            throw new InvalidOperationException("");
        }
    }
}