Ctrl+C 不适用于 wpf 中的数据网格。当我按下 Ctrl+C 键时，文本不是数据网格当前单元格的副本

This is my code. In this I am trying to implement Ctrl+C functionality but Ctrl+C not working. I used Keybinding in InputBindings of textblock but command is not called when I press Ctrl+C key. CanExecute and Executed Command called when bur parameter id null.

<UserControl.Resources>
    <ContextMenu  x:Key="ctMenu" DataContext="{Binding PlacementTarget,RelativeSource={RelativeSource Self}}">
        <MenuItem Header="Copy" InputGestureText="Ctrl+C"
                      Command="ApplicationCommands.Copy"
                      CommandTarget="{Binding}"                 
                      CommandParameter="{Binding Text}" />
    </ContextMenu>
</UserControl.Resources>

<Grid>
    <DataGrid Margin="30 10 30 0" x:Name="dg" Grid.Row="0" ItemsSource="{Binding CM.CustomerList}" AutoGenerateColumns="False" RowBackground="#F0F0F0"      Width="Auto"            HorizontalGridLinesBrush="Transparent" VerticalGridLinesBrush="Transparent"  AreRowDetailsFrozen="False" FrozenColumnCount="0"  Style="{DynamicResource DataGridStyle1}" SelectedItem="{Binding CM.CustomerDetail,UpdateSourceTrigger=PropertyChanged,Mode=TwoWay}"
      ScrollViewer.IsDeferredScrollingEnabled="True" RowHeaderWidth="0" CanUserResizeColumns="False"
      ScrollViewer.HorizontalScrollBarVisibility="Auto"  ScrollViewer.VerticalScrollBarVisibility="Auto" IsReadOnly="True" Height="Auto" MaxHeight="{Binding Converter={StaticResource PercentageConverter}, ConverterParameter=0.68, RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type Window}},Path=ActualHeight}" BorderThickness="0">
        <DataGrid.CommandBindings>
            <CommandBinding Command="{x:Static ApplicationCommands.Copy}"       CanExecute="CanCopy" Executed="Copy"  />
        </DataGrid.CommandBindings>
        <DataGrid.Columns>
            <DataGridTemplateColumn  Width="120"  CellStyle="{StaticResource RegisterDateColumn}" SortMemberPath="registered_on" CanUserSort="False">
                <DataGridTemplateColumn.CellTemplate >
                    <DataTemplate >
                        <DockPanel>
                            <DockPanel DockPanel.Dock="Left" >

                                <TextBlock  Name="txt" Text="{Binding DateOfRegistered }"  Padding="10 0 0 0" VerticalAlignment="Center" FontWeight="Regular"  ContextMenu="{StaticResource ctMenu}"  FontFamily="{StaticResource RobotoFont}" IsEnabled="True"  >
                                    <TextBlock.InputBindings>
                                        <MouseBinding Gesture="LeftDoubleClick"  Command="{Binding DataContext.CM.ClientDetailsCommand,RelativeSource=              {RelativeSource  AncestorType=DataGrid}}"  CommandParameter="{Binding}" />
                                    </TextBlock.InputBindings>
                                </TextBlock>
                            </DockPanel>
                        </DockPanel>
                    </DataTemplate >

                    </DataGridTemplateColumn.CellTemplate >
            </DataGridTemplateColumn>
            </DataGrid.Columns>
    </DataGrid>
</Grid>