how to check all the checkbox in datagride in wpf

<window x:class="WpfApplication5.MainWindow" xmlns:x="#unknown">
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="550" Width="525">
    <grid height="500" uselayoutrounding="False">
        <Label Content="EID" Height="28" HorizontalAlignment="Left" Margin="136,90,0,0" Name="label1" VerticalAlignment="Top" Width="78" />
        <textbox height="23" horizontalalignment="Left" margin="220,90,0,0" name="textBox1" verticalalignment="Top" width="120" />
        <Label Content="Name" Height="28" HorizontalAlignment="Left" Margin="136,124,0,0" Name="label2" VerticalAlignment="Top" Width="78" />
        <textbox height="23" horizontalalignment="Left" margin="220,124,0,0" name="textBox2" verticalalignment="Top" width="209" />
        <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="220,153,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" />
        <datagrid autogeneratecolumns="False" height="200" margin="14,200,0,0" name="dataGrid1" verticalalignment="Top" width="477">
            <datagrid.columns>
                <datagridtemplatecolumn width="100">
                    <datagridtemplatecolumn.headertemplate>
                        <datatemplate>
                            <checkbox name="hcb" checked="hcb_Checked" horizontalalignment="Center"></checkbox>
                        </datatemplate>
                    </datagridtemplatecolumn.headertemplate>
                    <datagridtemplatecolumn.celltemplate>
                        <datatemplate>
                            <checkbox name="cb" horizontalalignment="Center"></checkbox>
                        </datatemplate>
                    </datagridtemplatecolumn.celltemplate>
                </datagridtemplatecolumn>
                <datagridtextcolumn header="EID" binding="{Binding ID}" width="200"></datagridtextcolumn>
                <datagridtextcolumn header="NAME" binding="{Binding NAME}" width="250"></datagridtextcolumn>
            </datagrid.columns>
        </datagrid>
        <grid.background>
            <radialgradientbrush>
                <gradientstop color="Chartreuse" offset="0" />
                <gradientstop color="White" offset="1" />
            </radialgradientbrush>
        </grid.background>
    </grid>
</window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
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 WpfApplication5
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        #region
        ServiceReference1.ServiceClient obj = new ServiceReference1.ServiceClient();
        #endregion
        public MainWindow()
        {
            InitializeComponent();
            fill();
        }
        void fill()
        {
            dataGrid1.ItemsSource = obj.view();
        }
        private void button1_Click(object sender, RoutedEventArgs e)
        {
            ServiceReference1.ValList x = new ServiceReference1.ValList();
            x.ID = Convert.ToInt32(textBox1.Text);
            x.NAME = textBox2.Text;
            obj.insert(x);
            MessageBox.Show("One record saved.");
            fill();
        }
 
       
 
        private void hcb_Checked(object sender, RoutedEventArgs e)
        {
 
            MessageBox.Show("hi");
          
        }
 
       
    }
}