---

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;

namespace WpfApp1
{
    public partial class MainWindow : Window
    {
        user312_dbEntities db;

        public MainWindow()
        {
            InitializeComponent();
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            Student15 student = new Student15();

            student.FirstName = txtFirst.Text;
            student.LastName = txtLast.Text;

            db.Student15.Add(student);
            db.SaveChanges();

            dgogrenci.ItemsSource = db.Student15.ToList();
        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            int num = Convert.ToInt32(txtId.Text);

            var dRow = db.Student15
                .Where(w => w.ID == num)
                .FirstOrDefault();

            db.Student15.Remove(dRow);
            db.SaveChanges();

            dgogrenci.ItemsSource = db.Student15.ToList();
        }

        private void Button_Click_2(object sender, RoutedEventArgs e)
        {
            int num = Convert.ToInt32(txtId.Text);

            var uRow = db.Student15
                .Where(w => w.ID == num)
                .FirstOrDefault();

            uRow.FirstName = txtFirst.Text;
            uRow.LastName = txtLast.Text;

            db.SaveChanges();

            dgogrenci.ItemsSource = db.Student15.ToList();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            db = new user312_dbEntities();

            dgogrenci.ItemsSource = db.Student15.ToList();
        }
    }
}
<Window x:Class="WpfApp1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp1"
        mc:Ignorable="d"
        Title="WPF Entity Framework"
        Height="350"
        Width="525"
        Loaded="Window_Loaded">

    <Grid>

        <DataGrid Name="dgogrenci"
                  HorizontalAlignment="Left"
                  AutoGenerateColumns="False"
                  Height="185"
                  Margin="22,37,0,0"
                  VerticalAlignment="Top"
                  Width="246">

            <DataGrid.Columns>

                <DataGridTextColumn Binding="{Binding ID}"
                                    Header="ID"
                                    Width="*"/>

                <DataGridTextColumn Binding="{Binding FirstName}"
                                    Header="First Name"
                                    Width="3*"/>

                <DataGridTextColumn Binding="{Binding LastName}"
                                    Header="Last Name"
                                    Width="3*"/>

            </DataGrid.Columns>

        </DataGrid>

        <TextBox Name="txtId"
                 HorizontalAlignment="Left"
                 Height="23"
                 Margin="371,61,0,0"
                 TextWrapping="Wrap"
                 VerticalAlignment="Top"
                 Width="120"/>

        <TextBox Name="txtFirst"
                 HorizontalAlignment="Left"
                 Height="23"
                 Margin="371,89,0,0"
                 TextWrapping="Wrap"
                 VerticalAlignment="Top"
                 Width="120"/>

        <TextBox Name="txtLast"
                 HorizontalAlignment="Left"
                 Height="23"
                 Margin="371,117,0,0"
                 TextWrapping="Wrap"
                 VerticalAlignment="Top"
                 Width="120"/>

        <Button Content="Insert"
                HorizontalAlignment="Left"
                Margin="371,145,0,0"
                VerticalAlignment="Top"
                Width="120"
                Height="36"
                Click="Button_Click"/>

        <Button Content="Delete"
                HorizontalAlignment="Left"
                Height="36"
                Margin="371,186,0,0"
                VerticalAlignment="Top"
                Width="120"
                Click="Button_Click_1"/>

        <Button Content="Update"
                HorizontalAlignment="Left"
                Height="39"
                Margin="371,227,0,0"
                VerticalAlignment="Top"
                Width="120"
                Click="Button_Click_2"/>

        <Label Content="ID"
               HorizontalAlignment="Left"
               Margin="303,61,0,0"
               VerticalAlignment="Top"/>

        <Label Content="First Name"
               HorizontalAlignment="Left"
               Margin="300,88,0,0"
               VerticalAlignment="Top"/>

        <Label Content="Last Name"
               HorizontalAlignment="Left"
               Margin="302,117,0,0"
               VerticalAlignment="Top"/>

    </Grid>

</Window>