使用代码隐藏显示隐藏 div [英] Show hide div using codebehind

问题描述

我有一个 DropDownList，我试图显示一个 div OnSelectedIndexChanged 但它说 OBJECT REQUIRED.

I have a DropDownList for which I am trying to show a div OnSelectedIndexChanged but it says OBJECT REQUIRED.

我正在绑定那个 div 中的 DataList:

I am binding the DataList in that div:

aspx:

<asp:DropDownList runat="server" ID="lstFilePrefix1" AutoPostBack="True" 
                  OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" >
  <asp:ListItem Text="Prefix1" Value="Prefix1" />
  <asp:ListItem Text="Prefix2" Value="Prefix2" />
  <asp:ListItem Text="Prefix3" Value="Prefix3" />
  <asp:ListItem Text="Prefix1 and Prefix2" Value="Prefix1 and Prefix2" />
  <asp:ListItem Text="Prefix2 and Prefix3" Value="Prefix2 and Prefix3" />
</asp:DropDownList>

<asp:DataList ID="DataList1" runat="server" RepeatColumns="4"  
              CssClass="datalist1"  OnItemDataBound="SOMENAMEItemBound"
              CellSpacing="6" onselectedindexchanged="DataList1_SelectedIndexChanged" 
              HorizontalAlign="Center" Width="500px">

背后的代码:

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
    if (lstFilePrefix1.SelectedItem.Text=="Prefix2")
    {
        int TotalRows = this.BindList(1);
        this.Prepare_Pager(TotalRows);
        Page.ClientScript.RegisterClientScriptBlock(GetType(), "JScript1", "ShowDiv('data');", true);
    }
}

javascript:

function ShowDiv(obj)
{
     var dataDiv = document.getElementById(obj);
     dataDiv.style.display = "block";
}

我做错了什么?

推荐答案

制作 div

runat="server" 

然后做

if (lstFilePrefix1.SelectedValue=="Prefix2")
{
    int TotalRows = this.BindList(1);
    this.Prepare_Pager(TotalRows);
    data.Style["display"] = "block";
}

您的方法不起作用，因为在呈现 div 之前，javascript 正在呈现在 body 标记的顶部.您必须包含代码来告诉 javascript 等待 DOM 完全准备好接受您的请求，这可能是使用 jQuery 最简单的方法.

Your method isn't working because the javascript is being rendered in the top of the body tag, before the div is rendered. You'd have to include code to tell the javascript to wait for the DOM to be completely ready to take on your request, which would probably be easiest to do with jQuery.

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