ravi ravi - 1 month ago 15
ASP.NET (C#) Question

Show hide div using codebehind

I have a

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

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">


code behind:

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";
}


What am I doing wrong?

Answer

Make the div

runat="server" 

and do

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

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.