How do I add an empty first entry do an <asp:DropDownList>?

Question

I have a dropdown, I have a datasource, I have AutoPostBack set to true.
I want to add a first entry to the datasource that says something like "--- select country ---" and selecting this entry won't cause postback.
This feels like it should be easy to do, yet I can't seem to be able to find a good solution.
Thanks.

Answer 1

In your aspx page (the important part is handling the DataBound event and setting CausesValidation="true" to force validation of a drop down list):

<asp:DropDownList ID="ddlCountries" runat="server" DataSourceID="dsCountries" AutoPostBack="true" OnDataBound="ddlCountries_DataBound" CausesValidation="true" />
<asp:RequiredFieldValidator ID="rfvCountries" runat="server" ControlToValidate="ddlCountries" Display="Dynamic" ErrorMessage="Please select a country." />

In your codebehind (it is important that the value of the inserted item is String.Empty for the required field validator to work!):

protected void ddlCountries_DataBound(Object sender, EventArgs e)
{
ddlCountries.Items.Insert(0, new ListItem("--- select country ---", String.Empty));
}

Note: If you don't want the validator's message to display, set the "Display" property to "None".