如何使用asp：update面板中的dropdownlist选择值来显示/隐藏asp控件 [英] How to visible/hide asp controls using dropdownlist selected value in asp:update panel

问题描述

我需要根据选择的其他下拉列表值显示/隐藏下拉列表

放在ajax更新面板中





我试过这样......

I need to Visible/hide dropdownlist based on the selection of some other dropdownlist value
that is placed inside the ajax update panel


I have tried like this...

<asp:UpdatePanel ID="upSetSession" runat="server">
                             <ContentTemplate>
                              <asp:DropDownList ID="ddl_position" runat="server" class="feedback_textfield" AutoPostBack="true" OnSelectedIndexChanged="ddl_SelectedIndexChanged" >
                                  <asp:ListItem>Select</asp:ListItem>
                                  <asp:ListItem>Prime Minister</asp:ListItem>
                                  <asp:ListItem>Chief Minister</asp:ListItem>
                                  <asp:ListItem>President</asp:ListItem>
                                  <asp:ListItem>Governor</asp:ListItem>
                              </asp:DropDownList>


                              </ContentTemplate>
                              <Triggers>
                <asp:AsyncPostBackTrigger ControlID="ddl_position"

                    EventName="SelectedIndexChanged" />
            </Triggers>
         </asp:UpdatePanel>
                                  </td><td width="10">
                                  <asp:RequiredFieldValidator ID="RequiredFieldValidator4" runat="server"

                                      ControlToValidate="ddl_position" ErrorMessage="*" ForeColor="Red"></asp:RequiredFieldValidator>
                                  </td>
                        </tr>

                        <asp:Panel ID="state" runat="server">

                        <tr >

                          <td width="80" align="left" valign="middle">Select State</td>
                          <td width="16" align="center" valign="middle">:</td>
                          <td width="150" align="left" valign="middle">
                              <asp:DropDownList ID="ddl_state" runat="server" class="feedback_textfield" >
                                  <asp:ListItem>Select</asp:ListItem>
                                  
                              </asp:DropDownList>
                                  </td><td width="10">
                                  <asp:RequiredFieldValidator ID="RequiredFieldValidator10" runat="server"

                                      ControlToValidate="ddl_state" ErrorMessage="*" ForeColor="Red"></asp:RequiredFieldValidator>
                                  </td>


                        </tr>
                        </asp:Panel>

代码文件......

code file...

protected void Page_Load(object sender, EventArgs e)
    {
        state.Visible = false;

    }
    protected void ddl_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (ddl_position.SelectedItem.Value == "Chief Minister" || ddl_position.SelectedItem.Value == "Governor")
        {

            state.Visible = true;

        }

        else
        {

            state.Visible = false;
        }
    }

但它没有用..

任何人都可以告诉我该怎么做...



先谢谢你...

But its not working..
can anyone kindly tell me how to do this...

Thanks in Advance...

推荐答案

你好，

我想你忘了在 PageLoad IsPostBack 属性c $ c>事件。因此，面板总是不可见的。

因此，通过这种方式修改 PageLoad 事件

Hello ,
I think you forgot to set the IsPostBack property in the PageLoad event . As a result the panel is always invisible .
So , modify the PageLoad event by this way

protected void Page_Load(object sender, EventArgs e)
    {
       if(!IsPostBack)
        { 
         state.Visible = false;
        }
    }

谢谢

thanks

我使用过嵌套更新面板....

I have Used nested update panel....

<asp:UpdatePanel ID="upSetSession" runat="server">
                            <ContentTemplate>
                             <asp:DropDownList ID="ddl_position" runat="server" class="feedback_textfield" AutoPostBack="true" OnSelectedIndexChanged="ddl_SelectedIndexChanged" >
                                 <asp:ListItem>Select</asp:ListItem>
                                 <asp:ListItem>Prime Minister</asp:ListItem>
                                 <asp:ListItem>Chief Minister</asp:ListItem>
                                 <asp:ListItem>President</asp:ListItem>
                                 <asp:ListItem>Governor</asp:ListItem>
                             </asp:DropDownList>






                                 </td><td width="10">
                                 <asp:RequiredFieldValidator ID="RequiredFieldValidator4" runat="server"

                                     ControlToValidate="ddl_position" ErrorMessage="*" ForeColor="Red"></asp:RequiredFieldValidator>
                                 </td>
                       </tr> <asp:UpdatePanel ID="UpdatePanel1" runat="server">
                            <ContentTemplate>
                       <asp:Panel ID="state" runat="server" Visible="false">

                       <tr >


                             <asp:DropDownList ID="ddl_state" runat="server" class="feedback_textfield" >
                                 <asp:ListItem>Select State</asp:ListItem>
                                 <asp:ListItem>Prime Minister</asp:ListItem>
                                 <asp:ListItem>Chief Minister</asp:ListItem>
                                 <asp:ListItem>President</asp:ListItem>
                                 <asp:ListItem>Governor</asp:ListItem>
                             </asp:DropDownList>

                                 <asp:RequiredFieldValidator ID="RequiredFieldValidator10" runat="server"

                                     ControlToValidate="ddl_state" ErrorMessage="*" ForeColor="Red"></asp:RequiredFieldValidator>



                       </tr>
                       </asp:Panel>
                       </ContentTemplate>
                       </asp:UpdatePanel>
                       </ContentTemplate>
                             <Triggers>
               <asp:AsyncPostBackTrigger ControlID="ddl_position"

                   EventName="SelectedIndexChanged" />
           </Triggers>
        </asp:UpdatePanel>

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