gRPC with WPF not working

Question

I am trying to get the gRPC C# example working inside WPF.
The same code which is working inside a Console Application is not working.
What am I missing. The minimal class which works in the Console App and does not work in WPF looks like this:

public class GrpcClientImpl
    {
        private GrpcService.GrpcService.GrpcServiceClient client;
        public GrpcTestClientImpl()
        {
            var channel = new Channel("127.0.0.1:6980", ChannelCredentials.Insecure);
            client = new GrpcService.GrpcService.GrpcServiceClient(channel);
            ProcessFeed().Wait();
        }
        public async Task ProcessFeed()
        {
            try
            {
                using (var call = client.Feed(new FeedRequest()))
                {
                    var responseStream = call.ResponseStream;
                    while (await responseStream.MoveNext())
                    {
                        var result = responseStream.Current;
                        Console.WriteLine("received result");
                    }
                }
            }
            catch (RpcException e)
            {
                Console.WriteLine("RPC failed " + e);
                throw;
            }
        }
    }

The responseStream.MoveNext() is where it is hanging. It does not respond to sent items and it does also not trigger an exception if the gRPC server is not there. What have I missed?

Answer 1

The problem is the blocking call ProcessFeed().Wait(); within the constructor.

This post explains why: http://blog.stephencleary.com/2012/07/dont-block-on-async-code.html

To solve the issue, call await ProcessFeed(); from outside (not in the costructor).