如何通过单击下拉菜单隐藏面板

Question

>我有一个下拉菜单，它有一组项目。我想在单击下拉菜单时隐藏特定面板。

下面是我的 c# 代码，我的面板是用 asp.net 设计的。

我想在单击面板X中的下拉列表项Not Applicable时禁用面板XII

 protected void ddsscboard_SelectedIndexChanged(object sender, EventArgs e)
    {
        try {
            string sscpanel = ddsscboard.SelectedItem.Text;
            panelshow(sscpanel);
        }
        catch(Exception ex)
        {
        }
    }
    public void panelshow(string sscpanel)
    {
        if (sscpanel == "Not Applicable")
            XII.Visible = false;
        else
            lblmsg.Text = sscpanel;
    }
}

面板：-

X 类

                                      <div class="form-group">
                                        <label>Select Board</label> 
                                      <asp:DropDownList ID="ddsscboard" CssClass="form-control" OnSelectedIndexChanged="ddsscboard_SelectedIndexChanged" runat="server">
                                          <asp:ListItem>Not Applicable</asp:ListItem>
                                          <asp:ListItem>SSC</asp:ListItem>
                                        <asp:ListItem>CBSC</asp:ListItem>
                                           <asp:ListItem>ICSC</asp:ListItem>
                                           <asp:ListItem>Other</asp:ListItem>
                                         </asp:DropDownList>
                                    </div>
                                    <div class="form-group">
                                        <label>Complition Month</label>
                                       <asp:TextBox ID="txtssccomplitionmonth" CssClass="form-control" runat="server"></asp:TextBox>
                                    </div>
                                     <div class="form-group">
                                        <label>Complition Year</label>
                                       <asp:TextBox ID="txtssccomplitionyear" CssClass="form-control" runat="server"></asp:TextBox>
                                    </div>
                                     <div class="form-group">
                                        <label>Marks Obtained</label>
                                       <asp:TextBox ID="txtsscmarksobtained" CssClass="form-control" runat="server"></asp:TextBox>
                                    </div>
                                     <div class="form-group">
                                        <label>Total Marks</label>
                                       <asp:TextBox ID="txtssctotalmarks" CssClass="form-control" runat="server"></asp:TextBox>
                                    </div>
                                     <div class="form-group">
                                        <label>Upload File</label>
                                         <asp:FileUpload ID="sscfile"  runat="server" />
                                    </div>
                            </div>
                            <!-- /.col-lg-6 (nested) -->
                          </div>
                        <!-- /.row (nested) -->
                       </div>
                    </asp:Panel>
                    <!-- /.panel-body -->
                </div>
                <!-- /.panel -->
               </div>
      <div class="col-lg-12">
                <asp:Panel ID="XII" runat="server" CssClass="panel panel-default">
                    <div class="panel-heading">
                        Class XII
                    </div>
                    <div class="panel-body">
                        <div class="row">
                            <div class="col-lg-6">
                                      <div class="form-group">
                                        <label>Select Board</label>
                                      <asp:DropDownList ID="ddhscboard" CssClass="form-control" runat="server">
                                          <asp:ListItem>Not Applicable</asp:ListItem>
                                          <asp:ListItem>HSC</asp:ListItem>
                                        <asp:ListItem>CBSC</asp:ListItem>
                                           <asp:ListItem>ICSC</asp:ListItem>
                                           <asp:ListItem>Other</asp:ListItem>
                                         </asp:DropDownList>
                                    </div>
                                    <div class="form-group">
                                        <label>Complition Month</label>
                                       <asp:TextBox ID="txthsccomplitionmonth" CssClass="form-control" runat="server"></asp:TextBox>
                                    </div>
                                     <div class="form-group">
                                        <label>Complition Year</label>
                                       <asp:TextBox ID="txthsccomplitionyear" CssClass="form-control" runat="server"></asp:TextBox>
                                    </div>
                                     <div class="form-group">
                                        <label>Marks Obtained</label>
                                       <asp:TextBox ID="txthscmarksobtained" CssClass="form-control" runat="server"></asp:TextBox>
                                    </div>
                                     <div class="form-group">
                                        <label>Total Marks</label>
                                       <asp:TextBox ID="txthsctotalmarks" CssClass="form-control" runat="server"></asp:TextBox>
                                    </div>
                                     <div class="form-group">
                                        <label>Upload File</label>
                                         <asp:FileUpload ID="hscfile"  runat="server" />
                                    </div>
                            </div>
                            <!-- /.col-lg-6 (nested) -->
                        </div>
                        <!-- /.row (nested) -->
                        </div>
                    </asp:Panel>
                    <!-- /.panel-body -->
                </div>

Answer 1

您需要将 DropDownList 中的 AutoPostBack 属性设置为 true。请注意，您可能还希望建立一个空白列表项，以便默认情况下不会选择"不适用"：

<asp:DropDownList AutoPostBack="true" ID="ddsscboard" CssClass="form-control" OnSelectedIndexChanged="ddsscboard_SelectedIndexChanged" runat="server">
    <asp:ListItem></asp:ListItem>
    <asp:ListItem>Not Applicable</asp:ListItem>
    <asp:ListItem>SSC</asp:ListItem>
    <asp:ListItem>CBSC</asp:ListItem>
    <asp:ListItem>ICSC</asp:ListItem>
    <asp:ListItem>Other</asp:ListItem>
 </asp:DropDownList>