[FxCop.设计规则]

http://blog.csdn.net/cajon/category/122838.aspx?PageNumber=1

1.     抽象类不应该拥有构造函数

原文引用:

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:

一个公共抽象类型拥有一个公共的构造函数

描述:

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:

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。

posted @ 2008-05-06 17:34  彷徨......  阅读(508)  评论(0编辑  收藏  举报