<DataGrid Grid.Row="1"Grid.Column="1" Name="Grid"ItemsSource="{Binding}" 
AutoGenerateColumns="False" >
           
<DataGrid.Columns>
               
<DataGridTextColumn Header="Name" Width="100"Binding="{Binding Path=Name}"></DataGridTextColumn>
                <DataGridTextColumn Header="OldValue" Width="100" Binding="{Binding
Path=OldValue}"></DataGridTextColumn>
               
<DataGridTextColumn Header="NewValue" Width="100*" Binding="{Binding
Path=NewValue}"></DataGridTextColumn>
            </DataGrid.Columns>
       
</DataGrid>

How can i make cells readonly 

Any help will be appreciated.