单项选择题 You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5.  You add a TextBox control named TextBox1.  You write the following code segment for validation.  protected void CustomValidator1_ServerValidate(  object source, ServerValidateEventArgs args) {  DateTime dt = String.IsNullOrEmpty(args.Value)  DateTime.Now : Convert.ToDateTime(args.Value);  args.IsValid = (DateTime.Now - dt).Days < 10;  }  You need to validate the value of TextBox1.  Which code fragment should you add to the Web page?（）

单项选择题 You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5.  You create a custom control named OrderForm.  You write the following code segment.  Public Delegate Sub _  CheckOrderFormEventHandler(ByVal e As EventArgs)  Private Shared ReadOnly CheckOrderFormKey As New Object()  public event CheckOrderFormEventHandler  Public Custom Event CheckOrderForm As CheckOrderFormEventHandler  AddHandler(ByVal value As CheckOrderFormEventHandler)  Events.[AddHandler](CheckOrderFormKey, value)  End AddHandler  | English | Chinese | Japan | Korean | - 21 - Test Information Co., Ltd. All rights reserved. RemoveHandler(ByVal value As CheckOrderFormEventHandler)  Events.[RemoveHandler](CheckOrderFormKey, value)  End RemoveHandler  RaiseEvent(ByVal e As EventArgs)  End RaiseEvent  End Event  You need to provide a method that enables the OrderForm control to raise the CheckOrderForm event.  Which code segment should you use?（）

单项选择题 You create a custom control named OrderForm.  You write the following code segment.  public delegate void  CheckOrderFormEventHandler(EventArgs e);  private static readonly object CheckOrderFormKey  = new object();  public event CheckOrderFormEventHandler  CheckOrderForm {  add {  Events.AddHandler(CheckOrderFormKey, value);  }  remove {  Events.RemoveHandler(CheckOrderFormKey,  value);  }  }  You need to provide a method that enables the OrderForm control to raise the CheckOrderForm event.  Which code segment should you use?（）