[FxCop.设计规则]1. 抽象类不应该拥有构造函数

1. 抽象类不应该拥有构造函数

原文引用：

http://www.gotdotnet.com/team/fxcop/docs/rules.aspx?version=unstable&url=/Design/AbstractTypesShouldNotHaveConstructors.html Abstract types should not have constructors TypeName: AbstractTypesShouldNotHaveConstructors CheckId: CA1012 Category: Microsoft.Design Message Level: CriticalWarning Certainty: 95% Breaking Change: NonBreaking Cause: A public type is abstract and has a public constructor. Rule Description Constructors on abstract types can only be called by derived types. Because public constructors create instances of a type, and you cannot create instances of an abstract type, an abstract type with a public constructor is incorrectly designed. How to Fix Violations To fix a violation of this rule, either make the constructor protected, or do not declare the type as abstract. When to Exclude Messages Do not exclude a message from this rule. Example Code The following example contains an abstract type that violates this rule, and an abstract type that is correctly implemented. [C#] using System; namespace DesignLibrary public abstract class BadAbstractClassWithConstructor // Violates rule: AbstractTypesShouldNotHaveConstructors. public BadAbstractClassWithConstructor() // Add constructor logic here. } } public abstract class GoodAbstractClassWithConstructor protected GoodAbstractClassWithConstructor() // Add constructor logic here. } } }

引起的原因：（Cause）

一个公共抽象类型拥有一个公共的构造函数

描述：（Rule Description ）

构造函数被用来建立一个对象实例，但是你不能建立一个抽象类型的实例，抽象类型的构造函数就仅仅能够被它的继承类型使用。因此，为一个抽象类构造公共构造函数是一个错误的设计。

修复：（How to Fix Violations）

如果需要修复这个问题，可以声明这个构造函数为保护型，或者，声明这个类型不是一个抽象类型。