Question

请问C#中 抽象类有没有构造方法 构造方法中能不能带参数

Answer 1

抽象类是不可以被直接构造的，所以他的构造函数没有意义。很多语言中都不允许为抽象类添加构造函数，但是C#允许为抽象类添加构造函数。不过这是不推荐的做法，因为这样做会破坏设计原则！
以下为FXCop设计规则中对抽象类含有构造函数的警告：

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.

}

}

}

Answer 2

abstract (C# 参考)
abstract 修饰词可用於类别、方法、属性、索引子 (Indexer) 和事件。在类别宣告里使用 abstract 修饰词，表示该类别只是当做其他类别的基底类别而已。成员如果标记为抽象，或是包含在抽象类别 (Abstract Class) 内，则必须由衍生自此抽象类别的类别实作这个成员。

抽象类根本没有实作,又要衍生类来实作,构造函数又不可以继承,在抽象类中加构造函数和参数都是没有用的.我试过加上也不会报错.

Answer 3

完全可以。虽然抽象类本身不能被实例化。
但是不能不让他的子类去调用基类的构造函数吧

Answer 4

抽象当然也有构造方法