Using DropDownList in EditTemplates of a GridView


I am working on a GridView in Asp.Net. When initially a the Page Loads, my gridview look like: alt text

When a user clicks, to edit a row, I am using edit templates to show 'Domain' in a DropDownList. But problem is , when the DropDownlist gets load with data, it lost the current value of the 'Domain'.
i.e If I want to edit 4th Row, its domain which is currently set to 'Computers' is getting changed to 'MBA' which is ofcourse the first element return by the DataSource. alt text

I want to display the current value ('computers') as the selected value in DropDownList. But I am unable to get the value of Domain, which is being edited.

to solve exception use AppendDataBoundItems="true".

<asp:DropDownList ID="ddlCategory" runat="server" SelectedValue='<%# Eval("Domain") %>'
            DataTextField="text" DataValueField="value" AppendDataBoundItems="true">
            <asp:ListItem Text="Select..." Value=""></asp:ListItem>