System.Net.WebException in android xamarin application

Question

I am creating a simple login android application via Xamarin. I made an asmx web service with a login method that checks if a user exists in the database found in SQL Server and hosted it on IIS server. I tried accessing it through my phone's browser and everything went okay. then I created my app and added the web service as a web reference. but when I deployed my android app on my phone this exception occurred.

I enabled the Internet property for my application.

the details of the exception are as follows:

{System.Reflection.TargetInvocationException: An exception occurred during the operation, making the result invalid. Check InnerException for exception details. ---> System.Net.WebException: Error: ConnectFailure (No route to host) ---> System.Net.Sockets.SocketException: No route to host at System.Net.Sockets.SocketAsyncResult.CheckIfThrowDelayedException () [0x00014] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/System/System.Net.Sockets/SocketAsyncResult.cs:127 at System.Net.Sockets.Socket.EndConnect (System.IAsyncResult asyncResult) [0x0002c] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/System/System.Net.Sockets/Socket.cs:1211 at System.Net.Sockets.SocketTaskExtensions+<>c.b__2_1 (System.IAsyncResult asyncResult) [0x00000] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/System/System.Net.Sockets/SocketTaskExtensions.cs:36 at System.Threading.Tasks.TaskFactory1[TResult].FromAsyncCoreLogic (System.IAsyncResult iar, System.Func2[T,TResult] endFunction, System.Action1[T] endAction, System.Threading.Tasks.Task1[TResult] promise, System.Boolean requiresSynchronization) [0x00019] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/external/corert/src/System.Private.CoreLib/src/System/Threading/Tasks/FutureFactory.cs:538

--- End of stack trace from previous location where exception was thrown ---

at System.Net.WebConnection.Connect (System.Net.WebOperation operation, System.Threading.CancellationToken cancellationToken) [0x00151] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/System/System.Net/WebConnection.cs:169 --- End of inner exception stack trace --- at System.Net.WebConnection.Connect (System.Net.WebOperation operation, System.Threading.CancellationToken cancellationToken) [0x00217] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/System/System.Net/WebConnection.cs:188 at System.Net.WebConnection.InitConnection (System.Net.WebOperation operation, System.Threading.CancellationToken cancellationToken) [0x000cc] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/System/System.Net/WebConnection.cs:259 at System.Net.WebOperation.Run () [0x00052] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/System/System.Net/WebOperation.cs:268 at System.Net.WebCompletionSource1[T].WaitForCompletion () [0x0008e] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/System/System.Net/WebCompletionSource.cs:111 at System.Net.HttpWebRequest.RunWithTimeoutWorker[T] (System.Threading.Tasks.Task1[TResult] workerTask, System.Int32 timeout, System.Action abort, System.Func`1[TResult] aborted, System.Threading.CancellationTokenSource cts) [0x000e8] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/System/System.Net/HttpWebRequest.cs:956 at System.Net.HttpWebRequest.EndGetRequestStream (System.IAsyncResult asyncResult) [0x00019] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/System/System.Net/HttpWebRequest.cs:901 at System.Web.Services.Protocols.SoapHttpClientProtocol.AsyncGetRequestStreamDone (System.IAsyncResult ar) [0x0000c] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/System.Web.Services/System.Web.Services.Protocols/SoapHttpClientProtocol.cs:118 --- End of inner exception stack trace --- at System.ComponentModel.AsyncCompletedEventArgs.RaiseExceptionIfNecessary () [0x00008] in /Users/builder/jenkins/workspace/archive-mono/2019-08/android/release/mcs/class/referencesource/System/compmod/system/componentmodel/AsyncCompletedEventArgs.cs:60 at newapplogin.selling.LoginCompletedEventArgs.get_Result () [0x00001] in C:\Users\User\source\repos\Solution1\newapplogin\Web References\selling\Reference.cs:178 at newapplogin.MainActivity.Ws_LoginCompleted (System.Object sender, newapplogin.selling.LoginCompletedEventArgs e) [0x00001] in C:\Users\User\source\repos\Solution1\newapplogin\MainActivity.cs:62
at newapplogin.selling.WebService1.OnLoginOperationCompleted (System.Object arg) [0x00016] in C:\Users\User\source\repos\Solution1\newapplogin\Web References\selling\Reference.cs:102 at Android.App.SyncContext+<>c__DisplayClass3_0.b__0 () [0x00000] in <11f101b564894ca7af6c482ddc51c698>:0 at Java.Lang.Thread+RunnableImplementor.Run () [0x00008] in <11f101b564894ca7af6c482ddc51c698>:0 at Java.Lang.IRunnableInvoker.n_Run (System.IntPtr jnienv, System.IntPtr native__this) [0x00009] in <11f101b564894ca7af6c482ddc51c698>:0 at (wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.15(intptr,intptr)} System.Reflection.TargetInvocationException

this is my android mainactivity code:

using Android.App;
using Android.OS;
using Android.Support.V7.App;
using Android.Runtime;
using Android.Widget;
using System;
using Xamarin.Essentials;
using Xamarin.Android;
using Android.Content;

namespace newapplogin
{
    [Activity(Label = "@string/app_name", Theme = "@style/AppTheme", MainLauncher = true)]
    public class MainActivity : AppCompatActivity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            Xamarin.Essentials.Platform.Init(this, savedInstanceState); 
            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.activity_main);
            // Get our button from the layout resource,

            // and attach an event to it

            Button bulogin = FindViewById<Button>(Resource.Id.bulogin);

            Button buRegister = FindViewById<Button>(Resource.Id.buRegister);



            //buRegister.Click += BuRegister_Click;

            bulogin.Click += Bulogin_Click;


        }
        private void Bulogin_Click(object sender, EventArgs e)

        {

            var etUsername = FindViewById<EditText>(Resource.Id.etUsername);

            var etPassword = FindViewById<EditText>(Resource.Id.etPassword);

            selling.WebService1 ws = new selling.WebService1();
            ws.LoginAsync(etUsername.Text, etPassword.Text);
            ws.LoginCompleted += Ws_LoginCompleted;



        }



        private void Ws_LoginCompleted(object sender, selling.LoginCompletedEventArgs e)

        {



            if (e.Result.ValidUser)

            {

                Toast.MakeText(getApplicationContext(), "successful", 0).Show();



            }

            else


            {
                Toast.MakeText(getApplicationContext(), "failed", 0).Show();

            }

        }

        private Context getApplicationContext()
        {
            throw new NotImplementedException();
        }

        public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults)
        {
            Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);

            base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }
}

and this is my webservice code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Data.SqlClient;



namespace WebApplication1
{
    /// <summary>
    /// Summary description for WebService1
    /// </summary>
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    // [System.Web.Script.Services.ScriptService]
    public class WebService1 : System.Web.Services.WebService
    {

        [WebMethod]
        public Result Login(string userName, string userPass)
        {
            SqlConnection conn=new SqlConnection (new DBConnection().ConnectionString);
            Result result = new Result();
            try
            {
                SqlCommand cmd = new SqlCommand("SELECT username, password FROM people where CONVERT(VARCHAR, username)=@username and CONVERT(VARCHAR, password)=@password");
                cmd.Parameters.AddWithValue("username", userName);
                cmd.Parameters.AddWithValue("password", userPass);
                cmd.Connection = conn;
                if (conn.State==System.Data.ConnectionState.Closed)
                {
                    conn.Open();
                }
                SqlDataReader dr = cmd.ExecuteReader();
                if (dr.HasRows)
                {
                    result.ValidUser = true;
                    return result;
                }
                else
                {
                    result.ValidUser = false;

                }

            }
            catch(Exception ex)
            {
                result.Error = ex.ToString();

            }

            finally
            {
                conn.Close();
            }
            return result;
        }

    }
}

What could be the reason?

Answer 1

the problem was with my ip. it was changing because it was set to be dynamic. so whenever my app tries to access the webservice, it doesn't find it. so I just set my laptop's ip to be static and problem was solved. thanks for your help