派生

• Derived classes supporting specific protocols , such as
  支持特定协议的派生类（如
• And therefore should always be the last block before
  派生的异常，因此它应始终是
• When overridden in a derived class , paints a
  在派生类中被重写时，将绘制具有指定
• And add new properties to the derived class
  派生类并向派生类添加新属性时都重写
• A derived class can invalidate the cached version by calling
  派生类可以通过调用
• When overridden in a derived class , retrieves the
  当在派生类中重写时，检索事件的
• Class and classes that are derived from it use the url of a
  类和从它派生的类使用
• Method to dispose of the derived class s resources
  方法以释放该派生类的资源。
• Control , it does not support owner drawing
  控件派生的，但它不支持所有者描述。
• How to : access a variable hidden by a derived class
  如何：访问被派生类隐藏的变量