WPF Datagrid using an ObservableCollection and Linq to SQL

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C#

SQL

WPF

LINQ

DataGrid

Hello everyone, I am trying to create a Datagrid in my WPF test project that will update existing data and add new data.

My Sql table has 2 columns, ID (int) and Test1 (nvchar 50).

Here is my xaml:

><Window x:Class="Testing.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <DataGrid x:Name="dgTest" DisplayMemberPath="Testing" SelectedValue="{Binding ElementName=Test1, Path=SelectedItem.ID, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" SelectedValuePath="ID" HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top" Height="268" Width="498"/>
        <Button x:Name="btnSave" Content="Save" HorizontalAlignment="Left" Margin="222,291,0,0" VerticalAlignment="Top" Width="75" Click="btnSave_Click"/>

    </Grid>
</Window></

Here is my Code behind:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Collections.ObjectModel;

namespace Testing
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            // Initializes all the objects.

            InitializeComponent();

            // Runs my Loadtest method.

            LoadTest();
        }

        #region Variables


        #endregion

        #region Constructors

        // Creates a new instance of my data context
        
        dcTestDataContext dcTest = new dcTestDataContext();

        #endregion

        #region Classes

        public class ObservableTest : ObservableCollection<Test>
        {
            public ObservableTest(dcTestDataContext dcTest)
            {
                //Creates an ObservableCollection class
                //Then adds the Test1 field and ID field from the ling to sql table.

                foreach (Test Test1 in dcTest.Tests)
                {
                   this.Add(Test1);
                }

            }
        }

        #endregion

        #region Methods

        private void LoadTest()
        {  
  
            //Creates an object of my ObservableTest class
            //Assigns the data within my class to the item source of the datagrid

            ObservableTest oTest = new ObservableTest(dcTest);
            dgTest.ItemsSource = oTest.ToList();

        }


        private void SaveTest()
        {
            // Create a new instance of my ObservableTest class.
            // Create a new instance of Test and assign it the value of the selected item.
            // Create a variable i and assign it the ID of the selected item.

            // Creates a new instance of Test and iterates through the table to match the ID of the
            // selected item and the ID in the dcTest (datacontext).
            // Sets the Test1 field in the table with the Test1 field from the dcTest.

            // Submits the changes from dgTest to the dcTest and then creates a message box
            // to tell the user the update was succesful, before refreshing the datagrid.

            // Creates a messagebox to catch any exceptions, which gives the details of the exception.

                try
                {

                    ObservableTest ocTest = new ObservableTest(dcTest);

                    Test testRow = dgTest.SelectedItem as Test;

                    int i = testRow.ID;

                    Test test = (from p in dcTest.Tests

                                 where p.ID == testRow.ID

                                 select p).Single();

                    test.Test1 = testRow.Test1;

                    dcTest.SubmitChanges();

                    MessageBox.Show("Row Updated Successfully.");
                    LoadTest();

                }

                catch (Exception Ex)
                {

                    MessageBox.Show(Ex.Message);

                    return;
                }
            }



        #endregion

        #region Events

        private void btnSave_Click(object sender, RoutedEventArgs e)
        {
            // Runs my Savetest method, when the user clicks the save button.

            SaveTest();
        }

        #endregion       

      
    }
}

So my outcome is that my sql table will not update, but everything within my project works fine. I have tried stepping through my code numerous times, but to no availe.

Any help would be greatly appreciated.



Kind regards

Dean