请问如何在asp.net中所选择的单选按钮值 [英] how do i get the selected radiobutton value in asp.net

问题描述

这是我的code要知道，单选按钮已选定其中，但得到的错误在第6行对象引用不设置到对象的实例

this is my code to know, which radio-button has been selected, but getting error at line 6. Object reference not set to an instance of an object

Dim selected_option As String = "0"
        For i = 1 To 4
            Dim rdbName As String = "rb_option" & i
            Dim rdb As New RadioButton()
            rdb = CType(Me.Page.FindControl(rdbName), RadioButton)
            If rdb.Checked = True Then
                selected_option = i.ToString
                Exit For
            End If
        Next

有4单选按钮ID为 rb_option1 ， rb_option2 ， rb_option3 和 rb_option4 。

There are 4 radio-button with ID rb_option1,rb_option2,rb_option3 and rb_option4.

更新

<asp:Repeater ID="Repeater1" runat="server">
  <HeaderTemplate>
  <table style="width: 100%; height: 100%; margin-bottom: 50px">
  </HeaderTemplate>
  <ItemTemplate>
  <tr>
  <td style="width: 95%">
  <asp:Label ID="lbl_question" CssClass="frm_label" Text='<%# Eval("QUESTION")%>'runat="server"></asp:Label>
  </td>
  </tr>
  <tr>
  <td>
  </td>
  </tr>
  <tr>
  <td>
  <asp:RadioButton ID="rb_option1" Checked='<%# IF(Eval("ANSWER")="1",true,false) %>' GroupName="answer" Text='<%# Eval("OPT1") %>' CssClass="frm_label" runat="server" />
  </td>
  </tr>
  <tr>
  <td>
  <asp:RadioButton ID="rb_option2" Checked='<%# IF(Eval("ANSWER")="2",true,false) %>' GroupName="answer" Text='<%# Eval("OPT2") %>' CssClass="frm_label" runat="server" />
  </td>
  </tr>
  <tr>
  <td>
  <asp:RadioButton ID="rb_option3" Checked='<%# IF(Eval("ANSWER")="3",true,false) %>' GroupName="answer" Text='<%# Eval("OPT3") %>' CssClass="frm_label" runat="server" />
  </td>
  </tr>
  <tr>
  <td>
  <asp:RadioButton ID="rb_option4" Checked='<%# IF(Eval("ANSWER")="4",true,false) %>' GroupName="answer" Text='<%# Eval("OPT4") %>' CssClass="frm_label" runat="server" />
  </td>
  </tr>
  </ItemTemplate>
  <FooterTemplate>
  </table>
  </FooterTemplate>
  </asp:Repeater>

感谢提前！

推荐答案

终于，我做到了。

For i = 3 To Repeater1.Controls(1).Controls.Count - 1 Step 2
            Dim rdb As New RadioButton()
            rdb = CType((Repeater1.Controls(1).Controls(i)), RadioButton)
            'MsgBox(rdb.Checked)
            If rdb.Checked = True Then
                selected_option = count.ToString
                Exit For
            End If
            count = count + 1
        Next

和它的作品，我接到<帮助href=\"http://stackoverflow.com/questions/701412/how-to-find-controls-in-a-repeater-header-or-footer\">here

和，感谢大家对他们的努力。谢谢！

And, thanks to everyone for their effort. Thanks !!

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