DropDownList.SelectedIndex = -1

[wild_bill]

I would like to be able to set a drop down list to null, but prevent the user from selecting a null value. In my windows app I was able to use:

dropdownlist.selectedindex = -1

This doesn't appear to be working with my ASP page. ???

[Magiaus]

ddl.SelectedItem.Selected = false;

or

foreach(ListItem li in ddl.Items)
{
    if(li.Selected) li.Selected = !li.Selected;//aka false
}

[nemaroller]

The proper way:

dropdownlist1.ClearSelection();

You should realize that a dropdownlist allows you to set a null value listItem on the frontside aspx.

<asp:dropdownlist id="dropdownlist1" runat="server">
			<asp:listitem value="">--Select A Color--</asp:listitem>
			<asp:listitem value="red">Red</asp:listitem>
			<asp:listitem value="blue">Blue</asp:listitem>
			</asp:dropdownlist>

Then in the code behind, you can check whether the user selected an item by testing for an empty string value.

if (dropdownlist1.SelectedValue.Length == 0)
				Response.Redirect("http://www.google.com");

[Magiaus]

very nice to know this .ClearSelection is.....