How to Set the Default Value of a DropDownList in an ASP.NET Page
(Using Membership ObjectDataSource From MSDN Article)
I'm doing a project where I have lots of DropDownList's on a page and want a simple way to set the initial values based on some known value. The DropDownLists are retrieved using ObjectDataSource but I don't want the first value displayed. I wrestled some with how to do this using page_load or page_prerender but didn't come up with good solutions. I did finally decide that programming the databound event of the dropdownlist was probably the best way to go.
The solution is pasted below. The MembershipUtilities.MembershipODS c# code can be downloaded from MSDN or on my web site at the following location. http://peterkellner.net/2006/01/09/microsoft-aspnet-20-memberrole-management-with-iis/.
<%@ Page Language=”C#” %>
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN”
“http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>
<script runat=”server”>
protected void DropDownListUser_DataBound(object sender, EventArgs e)
{
DropDownListUser.SelectedIndex =
DropDownListUser.Items.IndexOf
(DropDownListUser.Items.FindByValue(Context.User.Identity.Name));
}
</script>
<html xmlns=”http://www.w3.org/1999/xhtml” >
<head runat=”server”>
<title>DropDownList Initialize</title>
</head>
<body>
<form id=”form1″ runat=”server”>
<div>
<asp:DropDownList ID=”DropDownListUser” runat=”server”
DataSourceID=”ObjectDataSourceUser”
DataTextField=”UserName” DataValueField=”UserName”
OnDataBound=”DropDownListUser_DataBound”>
</asp:DropDownList>
<asp:ObjectDataSource ID=”ObjectDataSourceUser” runat=”server”
SelectMethod=”GetMembers”
TypeName=”MembershipUtilities.MembershipUserODS”>
<SelectParameters>
<asp:Parameter Name=”sortData” Type=”String” />
</SelectParameters>
</asp:ObjectDataSource>
</div>
</form>
</body>
</html>
December 2nd, 2007 at 8:58 am
Why you don’t use just
DropDownListUser.SelectedValue = Context.User.Identity.Name;
instead of
DropDownListUser.SelectedIndex =
DropDownListUser.Items.IndexOf(
DropDownListUser.Items.FindByValue(Context.User.Identity.Name));
?
January 2nd, 2008 at 12:56 am
I dont agree with george, since it replaces the selectedvalue.
But Peter
why cant we use
DropDownListUser.Items.FindByValue(Context.User.Identity.Name).Selected = true;
is it not more simpler?
April 3rd, 2008 at 11:45 am
I agree with NaveenJ. His approach is just want i’m using :p
July 2nd, 2008 at 8:23 am
I use Naveen’s approach too but at run time when databind occurs, if the SelectedIndex is not cleared to -1 first then you can get an http error that you cannot have more than one item selected. It goes something like
DropDownList.SelectIndex = -1;
DropDownListUser.Items.FindByValue(Context.User.Identity.Name).Selected = true;