zoukankan      html  css  js  c++  java
  • C#中Abstract 与 Virtual

    Abstract classes have the following features:

    • An abstract class cannot be instantiated.

    • An abstract class may contain abstract methods and accessors.

    • It is not possible to modify an abstract class with the sealed (C# Reference) modifier, which means that the class cannot be inherited.

    • A non-abstract class derived from an abstract class must include actual implementations of all inherited abstract methods and accessors.

    Use the abstract modifier in a method or property declaration to indicate that the method or property does not contain implementation.

    Abstract methods have the following features:

    • An abstract method is implicitly a virtual method.

    • Abstract method declarations are only permitted in abstract classes.

    • Because an abstract method declaration provides no actual implementation, there is no method body; the method declaration simply ends with a semicolon and there are no curly braces ({ }) following the signature.

    •  The implementation is provided by an overriding method override (C# Reference), which is a member of a non-abstract class.

    • It is an error to use the static or virtual modifiers in an abstract method declaration.

    Abstract properties behave like abstract methods, except for the differences in declaration and invocation syntax.

    • It is an error to use the abstract modifier on a static property.

    • An abstract inherited property can be overridden in a derived class by including a property declaration that uses the override modifier.

    When a virtual method is invoked, the run-time type of the object is checked for an overriding member. The overriding member in the most derived class is called, which might be the original member, if no derived class has overridden the member.

    By default, methods are non-virtual. You cannot override a non-virtual method.

    You cannot use the virtual modifier with the static, abstract, private or override modifiers.

    Virtual properties behave like abstract methods, except for the differences in declaration and invocation syntax.

    • It is an error to use the virtual modifier on a static property.

    • A virtual inherited property can be overridden in a derived class by including a property declaration that uses the override modifier.

  • 相关阅读:
    单变量线性回归
    【记】国奖交流会
    转【研究生第一篇学术论文常犯问题总结】
    this.$confirm里面使用await异步调取接口数据
    margin和padding的值是百分比的时候是怎么计算的?
    原生js实现三级联动下拉框
    两个数组里面的对象元素根据相同的id合并到一个数组
    制作遮罩层的样式
    自定义表单验证方法的使用
    封装获取操作系统和浏览器类型的方法
  • 原文地址:https://www.cnblogs.com/stragon/p/2093648.html
Copyright © 2011-2022 走看看