C# 无法访问代码隐藏中数据列表内的单选按钮

我在数据列表中有一个单选按钮。我需要在代码隐藏中访问它们。但我所有的努力都没有奏效。这就是我正在做的：

<asp:DataList ID="dlPaper" runat="server" RepeatColumns="1" RepeatDirection="Vertical"
            Width="755px" onitemcommand="item_command">
            <ItemTemplate>
                <table>
                    <tr>
                        <td>
                            Question :
                        </td>
                        <td colspan ="4">
                            <asp:Label ID="lblQuestion" runat="server" Text='<%#Eval("Question") %>'></asp:Label>?
                              <asp:Label ID="lblQID" runat="server" Text='<%#Eval("QID") %>' Visible="False"></asp:Label>
                        </td>
                    </tr>
                    <tr>
                    <td></td>
                        <td>
                            A
                        </td>
                        <td>
                            <asp:Label ID="lblOption1" runat="server" Text='<%#Eval("Option1") %>'></asp:Label>
                        </td>
                        <td>
                            B
                        </td>
                        <td>
                            <asp:Label ID="lblOption2" runat="server" Text='<%#Eval("Option2") %>'></asp:Label>
                        </td>
                    </tr>
                     <tr> <td></td>
                        <td>
                            C
                        </td>
                        <td>
                            <asp:Label ID="lblOption3" runat="server" Text='<%#Eval("Option3") %>'></asp:Label>
                        </td>
                        <td>
                            D
                        </td>
                        <td>
                            <asp:Label ID="lblOption4" runat="server" Text='<%#Eval("Option4") %>'></asp:Label>
                        </td>
                    </tr>

                </table>
                <table>
                <tr>
                        <td>
                            Answer :
                        </td>
                        <td>    
                              <asp:RadioButton ID="rdOption1" runat="server" Text="A" GroupName="Ans"/>
                        </td>
                        <td>
                        <asp:RadioButton ID="rdOption2" runat="server" Text="B"  GroupName="Ans" />
                        </td>
                        <td>
                        <asp:RadioButton ID="rdOption3" runat="server" Text="C" GroupName="Ans" />
                        </td>
                        <td>
                        <asp:RadioButton ID="rdOption4" runat="server" Text="D" GroupName="Ans" />
                        </td>
                        <td>
                    <asp:Button ID="tbnAnswer" runat="server" Text="Submit Answer"  CommandName='<%#Eval("QID") %>'   OnCommand='item_command'/>
                    </td>
                    </tr>
                </table>
            </ItemTemplate>
        </asp:DataList>

但我无法访问“代码隐藏”中的单选按钮。

请这样尝试

protected void DataList1_ItemCommand(object source, DataListCommandEventArgs e)
    {

     if (e.CommandName == "YourCommandName")
            {
                r1 = (RadioButton)e.Item.FindControl("rdButton");
             }
   }

protected void DataList1_ItemCommand(object source, DataListCommandEventArgs e)
    {

     if (e.CommandName == "YourCommandName")
            {
                r1 = (RadioButton)e.Item.FindControl("rdButton");
             }
   }