An exception occurred during the operation,making the result invalid.

<configuration>
    <system.serviceModel>
        <bindings>
            <customBinding>
                <binding name="CustomBinding_webService">
                    <binaryMessageEncoding />
                    <httpTransport maxReceivedMessageSize="2147483647" maxBufferSize="2147483647" />
                </binding>
            </customBinding>
        </bindings>
        <client>
            <endpoint address="http://localhost:52878/webService.svc" binding="customBinding"
                bindingConfiguration="CustomBinding_webService" contract="ServiceReference1.webService"
                name="CustomBinding_webService" />
        </client>
    </system.serviceModel>
</configuration>

using System;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Activation;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Data;

using System.ServiceModel.DomainServices;

namespace Website.Web
{
    [ServiceContract(Namespace = "")]
    [ServiceBehavior(IncludeExceptionDetailInFaults = true, AddressFilterMode = AddressFilterMode.Any)]
    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
    public class webService
    {


          [OperationContract]

        public List<Data> GetRows()
        {
           DatabaseDataContext db = new DatabaseDataContext();
            var selected_rows = from rows in db.Datas select rows;
           return selected_rows.ToList();

        }

        [OperationContract]

        public void InsertData(string n1, string n2, string n3)
        {

            DatabaseDataContext db = new DatabaseDataContext();
            Data row = new Data
            {
                Key = Guid.NewGuid(),
                Alpha = n1,
                Beta = n2,
                Gamma = n3
            };

            db.Datas.InsertOnSubmit(row);
            db.SubmitChanges();
        }



        // Add more operations here and mark them with [OperationContract]
    }
}

namespace Website
{
    using System.Windows.Controls;
    using System.Windows.Navigation;
    using Website.ServiceReference1;
    using System.Data;

    /// <summary>
    /// Home page for the application.
    /// </summary>
    public partial class Home : Page
    {
        /// <summary>
        /// Creates a new <see cref="Home"/> instance.
        /// </summary>
        public Home()
        {
            InitializeComponent();

            this.Title = ApplicationStrings.HomePageTitle;
        }

        /// <summary>
        /// Executes when the user navigates to this page.
        /// </summary>
        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
        }

        private void Submit_Click(object sender, System.Windows.RoutedEventArgs e)
        {
            webServiceClient webclinet = new webServiceClient();
            webclinet.InsertDataAsync(textBox1.Text, textBox2.Text, textBox3.Text);

        }

        private void Get_Click(object sender, System.Windows.RoutedEventArgs e)
        {

            webServiceClient webclinet = new webServiceClient();

            webclinet.GetRowsAsync();
            webclinet.GetRowsCompleted += new System.EventHandler<GetRowsCompletedEventArgs>(webclinet_GetRowsCompleted);
           webclinet.GetRowsAsync();

        }
        void webclinet_GetRowsCompleted(object sender, GetRowsCompletedEventArgs e)
        {
            Grid1.ItemsSource = e.Result;
        }

    }
}