WPF Datagrid中怎么使用键盘选择行

WPF Datagrid中如何使用键盘选择行
如题
实现DataGrid在绑定数据后，直接可使用键盘方向键，上、下来选取数据。DataGrid中还有个模板列Radiobutton。
在键盘上下移动到某一行中，点击回车，即当前行的Radiobutton为选中状态。刚接触WPF，不太明白，求指教~
DataGrid的xaml如下：

   <DataGrid AutoGenerateColumns="False" CanUserAddRows="False"  ItemsSource="{Binding StopRecordsList}"  CanUserDeleteRows="False" Height="412" HorizontalAlignment="Left" Name="dataGrid1" VerticalAlignment="Top" Width="663" Canvas.Left="45" Canvas.Top="99">

                    <DataGrid.Columns>


                        <DataGridTextColumn Header="车牌号" Binding="{Binding StopRecord.RsuInCarNo}" Width="100"></DataGridTextColumn>

                        <DataGridTextColumn Header="进场时间" Binding="{Binding StopRecord.StopInTime}" Width="120"></DataGridTextColumn>

                        <DataGridTemplateColumn Header="图片" Width="200">

                            <DataGridTemplateColumn.CellTemplate>

                                <DataTemplate>

                                    <Image Source="{Binding carImage}" Height="150" Width="200"/>

                                </DataTemplate>

                            </DataGridTemplateColumn.CellTemplate>

                        </DataGridTemplateColumn>


                        <DataGridTemplateColumn Header="选中" SortMemberPath="IsSelected">

                            <DataGridTemplateColumn.CellTemplate>

                                <DataTemplate>

                                    <RadioButton Height="150" IsChecked="{Binding Path=IsSelected,UpdateSourceTrigger=PropertyChanged}" Command="{Binding Path=DataContext.SelectStopItemCommand,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type DataGrid}}}">

                                    </RadioButton>

                                </DataTemplate>

                            </DataGridTemplateColumn.CellTemplate>

                        </DataGridTemplateColumn>

                    </DataGrid.Columns>

                </DataGrid>

------解决思路----------------------
既然都能获得 行，就通过行 找RadioButton，通过查找 子元素方法。
参见：
http://blog.****.net/duanzi_peng/article/details/17094639