grpc/examples/csharp/HelloworldXamarin/HelloworldXamarin/MainPage.xaml.cs

#region Copyright notice and license
// Copyright 2020 The gRPC Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#endregion

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using Grpc.Core;
using Helloworld;

namespace HelloworldXamarin
{
    public partial class MainPage : ContentPage
    {
        const int Port = 30051;
        int count = 1;

        public MainPage()
        {
            InitializeComponent();
        }

        private void Button_Clicked(object sender, EventArgs e)
        {
            SayHello(sender as Button);
        }

        private void SayHello(Button button)
        {
            Server server = new Server
            {
                Services = { Greeter.BindService(new GreeterImpl()) },
                Ports = { new ServerPort("localhost", Port, ServerCredentials.Insecure) }
            };
            server.Start();

            // use loopback on host machine: https://developer.android.com/studio/run/emulator-networking
            // 10.0.2.2:30051
            Channel channel = new Channel("localhost:30051", ChannelCredentials.Insecure);

            var client = new Greeter.GreeterClient(channel);
            string user = "Xamarin " + count;

            var reply = client.SayHello(new HelloRequest { Name = user });

            button.Text = "Greeting: " + reply.Message;

            channel.ShutdownAsync().Wait();
            server.ShutdownAsync().Wait();

            count++;
        }

        class GreeterImpl : Greeter.GreeterBase
        {
            // Server side handler of the SayHello RPC
            public override Task<HelloReply> SayHello(HelloRequest request, ServerCallContext context)
            {
                return Task.FromResult(new HelloReply { Message = "Hello " + request.Name });
            }
        }
    }
}