How to connect to local network first instead of internet in C# Xamarin Android app?

Question

I have a Xamarin Android app. It connects to a “No Internet based Wifi router” for some IOT devices. But it also needs to use mobile’s cellular data for storing some informa

Answer 1

The solution I can think of is that you can try to use Xamarin.Essentials and check the profile of the connection, and use this to force the requests to your Wifi, and the other requests through cellular data

var profiles = Connectivity.ConnectionProfiles;
if (profiles.Contains(ConnectionProfile.WiFi))
{
    // Active Wi-Fi connection.
}

The documentation can be found here.

Answer 2

Use Plugin.Essentials ( require a NetStandard project) and refer to this link :

https://docs.microsoft.com/en-us/xamarin/essentials/connectivity?tabs=android

try local access and not network.

Answer 3

After lot of tries and failures, I was able to implement the approach provided here: Stackoverflow Link

I changed this code from Java to Xamarin C# and was able to force Cellular or Wifi as the preferred network programmatically.

My implementation:

using Android.Net;
public SomeClass{
    public static Context _context = Android.App.Application.Context;

    ....

    /// <summary>
    /// Forces the wifi over cellular.
    /// </summary>
    public static void ForceWifiOverCellular()
    {
        ConnectivityManager connection_manager = (ConnectivityManager)_context.GetSystemService(Context.ConnectivityService);

        NetworkRequest.Builder request = new NetworkRequest.Builder();
        request.AddTransportType(TransportType.Wifi);

        var callback = new ConnectivityManager.NetworkCallback();
        connection_manager.RegisterNetworkCallback(request.Build(), new CustomNetworkAvailableCallBack());

    }

    /// <summary>
    /// Forces the cellular over wifi.
    /// </summary>
    public static void ForceCellularOverWifi()
    {
        ConnectivityManager connection_manager = (ConnectivityManager)_context.GetSystemService(Context.ConnectivityService);

        NetworkRequest.Builder request = new NetworkRequest.Builder();
        request.AddTransportType(TransportType.Cellular);

        connection_manager.RegisterNetworkCallback(request.Build(), new CustomNetworkAvailableCallBack());
    }
}


/// <summary>
/// Custom network available call back.
/// </summary>
public class CustomNetworkAvailableCallBack : ConnectivityManager.NetworkCallback
{
    public static Context _context = Android.App.Application.Context;

    ConnectivityManager connection_manager = (ConnectivityManager)_context.GetSystemService(Context.ConnectivityService);

    public override void OnAvailable(Network network)
    {
        //ConnectivityManager.SetProcessDefaultNetwork(network);    //deprecated (but works even in Android P)
        connection_manager.BindProcessToNetwork(network);           //this works in Android P
    }
}

Usage:

1. Where I need to force Cellular, just call:

SomeClass.ForceCellularOverWifi();

2. Where I need to force Wifi, just call:

SomeClass.ForceWifiOverCellular();

Hope this helps others.