As is,where
来源:学生作业帮 编辑:搜搜考试网作业帮 分类:综合作业 时间:2024/07/08 02:30:04
As is,where
![As is,where](/uploads/image/z/4230938-2-8.jpg?t=As+is%2Cwhere)
返回true和false.如果一个对象是某个类型或是其父类型的话就返回为true,否则的话就会返回为false.另外is操作符永远不会抛出异常.代码如下:\x0dSystem.Boolean b1 = (o is System.Object);//b1 为true\x0dSystem.Boolean b2 = (o is Employee);//b2为false如果对象引用为null,那么is操作符总是返回为false,因为没有对象可以检查其类型,就像下面代码一样\x0dif(o is Employee) {\x0dEmployee e = (Employee) o;\x0d//在if语句中使用e\x0d}在上面代码中,其实clr对对象类型检查了两次:is操作首先检查o所引用的对象是否和employee类型兼容.如果兼容,那么在if语句内clr在执行转换时又会检查o是否为一个Employee引用.这种编程范式十分常见,c#便提供了一种新的类型检查,转换方式.即as操作符,他可以在简化代码的同时,提高性能.代码如下:\x0dEmployee e = o as Employee;\x0dif(e != null){//在if语句中使用e\x0d}这种as操作即便等同于上面代码,同时只进行了1次的类型检查,所以提高了性能.
As is,where
价格后面 加 As is where is
where is the beef is used when something is not as good as i
英语翻译1.He is as full of meat as an egg where the law is conce
Where there is light,there is darkness.As long as there are
英语单选—Mum,where is my schoolbag?选as还是where
Do you know where the water is?Write down as many as possibl
英语翻译Where you are dropped,as the saying is,is who you are,at
As the saying___,"where there is a will,there is a way."
As the saying goes,"Where there is a will,there is way." 汉语意
Where someone is born and what a person looks like is not as
Life is one fool thing after another where as love is two fo