Dynamically add items to DropDownList but still allow for a field that has no value?

Question

I have populated my DropDownLists with different columns of items from a database but I'm trying to make it so that the first item in the list has no value with text similar to "Select an Item"

For some reason Even though I add the item to the list and make it the selected item, It gets overridden by the items from the database...

How can I accomplish this?

UPDATE:

Everything is done from the .aspx page designer but here is the generated code-

          <asp:DropDownList ID="ddlUnits1" runat="server" DataSourceID="UnitsEDS" 
                   DataTextField="unitId" DataValueField="unitId">
                   <asp:ListItem Selected="True">Select Units</asp:ListItem>
          </asp:DropDownList>

          <asp:EntityDataSource ID="UnitsEDS" runat="server" 
                   ConnectionString="name=UnitsEntity" 
                   DefaultContainerName="UnitsEntity" EnableFlattening="False" EntitySetName="spillunits">
          </asp:EntityDataSource>

Answer 1

Use the ListControl.AppendDataBoundItems Property:

AppendDataBoundItems Documentation

From the documentation: "The AppendDataBoundItems property allows you to add items to the ListControl object before data binding occurs. After data binding, the items collection contains both the items from the data source and the previously added items."