WPF datagrid ContextMenu MenuItem CommandParameter Binding Datagrid

<DataGrid.ContextMenu>

CommandParameter="{Binding Path=PlacementTarget, RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type ContextMenu}}}"

 

                    <ContextMenu>
                        <MenuItem Header="Load"/>
                        <MenuItem Header="Export">
                            <MenuItem Header="Excel"
                                      Command="{Binding ExportExcelCommand}"
                                      CommandParameter="{Binding Path=PlacementTarget, RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type ContextMenu}}}"/>
                            <MenuItem Header="CSV"
                                      Command="{Binding ExportCSVCommand}"/>
                        </MenuItem>
                    </ContextMenu>
                </DataGrid.ContextMenu>