You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5. You write the following code fragment：  
01 <asp：RequiredFieldValidator  
02   ID="rfValidator1" runat="server"  
03   Display="Dynamic" ControlToValidate="TextBox1"  
04 ► 
05 >  
06 ► 
07 </asp：RequiredFieldValidator>  
08  
09 <asp：ValidationSummary DisplayMode="List"  
10   ID="ValidationSummary1" runat="server" />  
You need to ensure that the error message displayed in the validation control is also displayed in the ValidationSummary list. 
What should you do？（）

You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5. You create a custom-templated server control. 
You need to ensure that the child controls of the server control are uniquely identified within the control hierarchy of the page. 
Which interface should you implement？（）