I have a dropdown list. In a GridView and I was wanting the dropdown to be readonly when first displayed and then enable when the edit button is clicked?

Does anybody have any ideas on how to go about this?
Thanks in advance
G

                <asp:TemplateField HeaderText="Status Desc">
                    <ItemTemplate>
                      <asp:DropDownList ID="ErrStatatusDDL" DataTextField="ErrorStatus"
                        DataValueField = "ErrorStatusId" DataSource= '<%# GetErrorStatuses() %>' runat="server" SelectedValue='<%# Bind("StatusId") %>' EnableTheming="True">
                      </asp:DropDownList>
                    </ItemTemplate>
                </asp:TemplateField>

this is fine now put the read only dropdown under ItemTemplate and the enabled dropdown under EditItemTemplate.