Exception Handling in Async Methods

Question

I have a question regarding catching exceptions after a long await chain in C#.

        /// <summary>
        /// Waiting on this waits on a response, be warned!
        /// </summary>
        /// <param name="msg"></param>
        /// <returns></returns>
         public async Task<ComMessage> SendMessageForResponse(ComMessage msg)
         {
             lock (_responses)
             {
                 _responses[msg.transactionid] = null;
             }

           await SendMessage(msg);

           return await Task.Run<ComMessage>(() => {
                lock (_responses)
                {
                    while (_responses[msg.transactionid] == null) Monitor.Wait(_responses);
                    var response = _responses[msg.transactionid];
                    _responses.Remove(msg.transactionid);
                    return response;
                }

            });


        }

        /// <summary>
        /// Sends a message, serialized as JSON, to the game
        /// </summary>
        /// <param name="msg"></param>
        /// <returns></returns>
        public async Task SendMessage(ComMessage msg)
        {
            try
            {
                await _semaphore.WaitAsync();
                await Task.Run(() => { new DataContractJsonSerializer(msg.GetType()).WriteObject(_writer.BaseStream, msg); });
            }
            finally { _semaphore.Release(); }

        }

When an exception is raised at new DataContractJsonSerializer(msg.GetType()).WriteObject(_writer.BaseStream, msg); } I'd like that exception to be caught by the method which calls await SendMessageForResponse, such as the code below

 try
        {
            var t = await St0rmCom.Instance.SendMessageForResponse(com);


            MessagePlayerInfoResponse pi = (MessagePlayerInfoResponse)t;
            StringBuilder sb = new StringBuilder();
            Debug.LogInfo("Iterating {0} players", pi.playerinfo.Length);
            for (int i = 0, count = 0; i < pi.playerinfo.Length; ++i)
            {
                MessagePlayerData p = pi.playerinfo[i];
                ++count;
                sb.AppendFormat("\"{0}\" ", p.name);
                if (sb.Length > 250 || i == (pi.playerinfo.Length - 1))
                {
                    Debug.LogInfo("Sending a PI Line.");
                    cmd.Reply("({0}): {1} ", count, sb.ToString());
                    sb.Clear();
                    count = 0;
                }
            }
        }
        catch (Exception)
        {
            cmd.Reply("Request failed.");
            //Debug.LogError(e, "Request Failed");
        }

However, the exception is not caught there. Instead, the debugger breaks. Any advice?

Answer 1

The exception will be caught. Just continue in the debugger.