关于继承

问题情况：
试写一个关于SharePoint Feature的程序，继承了SPFeatureReceiver类.只使用了其实两个抽象方法

    public abstract void FeatureActivated(SPFeatureReceiverProperties properties);
    public abstract void FeatureDeactivating(SPFeatureReceiverProperties properties);
编绎的时候总是提示错误"不会实现抽象的成员*******"的提示。
解决方法：
需要实现被继承类中所有的抽象方法！
        public override void FeatureInstalled(SPFeatureReceiverProperties properties)
        {
            //throw new Exception("The method or operation is not implemented.");
        }
        public override void FeatureUninstalling(SPFeatureReceiverProperties properties)
        {
            //throw new Exception("The method or operation is not implemented.");
        }