Want to append string "Pending" if gridview template field is null or empty??

 In a gridview template field, I am dispaying datetime from sql db using a label with formatting as below.
If it returns Null or empty from DB then I want to append the text "Pending" instead
of empty space?

<asp:TemplateField HeaderText="Posted Date" SortExpression="StartDate">                              <ItemTemplate>                     <asp:Label ID="Label1" runat="server" Text='<%# String.Format("{0:MMM d, yyyy}", Eval("PostedDate"))  %> '></asp:Label>

                </ItemTemplat ...