Server Client Application with .NET and Xamarin

Question

I searched around the internet a lot of hours but I couldn't find anything that matches my case.

I simply want to implement a Server/Client App with TCP or UDP where my Android App (Xamarin) acts as a server and my .NET application as Client. Since I have not much experience with app development and no experience with Xamarin, I was looking for an example. All I found was this:

http://www.codeproject.com/Articles/340714/Android-How-to-communicate-with-NET-application-vi

First of all this is the opposite way (Server on .NET and Client as App) and additionaly it is for Android Studio so it's hard for me to translate these things into Xamarin without errors.

Please can someone help and give me an example how to realize my issue?

Thank you!

Answer 1

On Xamarin.Android you can use all of the regular .Net socket classes:

Namespaces:

using System.Net;
using System.Net.Sockets;

Example:

IPHostEntry ipHostInfo = Dns.GetHostEntry (Dns.GetHostName ());
IPAddress ipAddress = ipHostInfo.AddressList [0];
IPEndPoint localEndPoint = new IPEndPoint (ipAddress, 11000);
System.Diagnostics.Debug.WriteLine(ipAddress.ToString());
// Create a TCP/IP socket.
Socket listener = new Socket (AddressFamily.InterNetwork,
                     SocketType.Stream, ProtocolType.Tcp);

AndroidManifest.xml Required Permissions are:

<uses-permission android:name="android.permission.INTERNET"></uses-permission>

The MSDN-based Asynchronous Server Socket example works as a cut/paste example with no changes.

i.e.

Using the MSDN code, you can call the static method, AsynchronousSocketListener.StartListening, in a thread to start listening on port 11000 defined in the AsynchronousSocketListener class.

new Thread (new ThreadStart (delegate {
    AsynchronousSocketListener.StartListening();
})).Start ();

---

Once it is running on your device/emulator, you can telnet into your Android TCP socket server:

---

>telnet 10.71.34.100 11000

---

Trying 10.71.34.100...
Connected to 10.71.34.100.
Escape character is '^]'.

---

Once connected, type in This is a test<EOF> and the Android will echo it back:

This is a test<EOF>

Answer 2

You do this like in normal .net, except you have to ask permissions to use sockets.

There are tons of simple example of creating a listening tcp connection in c#.

The problem you will have is to know the IP address of your server (in the phone) as it will likely change often when the user is moving.