VB6成员变量继承

Question

VB6成员变量继承

4

我在继承一个（公共的）变量时遇到了问题，假设变量名为

Public Var As ClassThatIsIndependent

上面的声明本身没有问题，但是如果我继承了包含它的类，则可能会出现问题。

Implements BaseClass

我得到了错误信息“对象模块需要实现接口变量”。我已经尝试了以下选项（都在ChildClass内部）：

Public Var As ClassThatIsIndependent

并且

Public BaseClass_Var As ClassThatIsIndependent

但是它们都没能解决问题。有什么替代方案吗？我可以接受可能的Set/Get解决方案，但是我更希望将Var保持为公共变量。

- Rezniaq

1个回答

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- user65839 · Accepted Answer

根据Visual Basic 6.0程序员指南中的多态性，实现属性部分：Implementing Properties。

Suppose we give the Animal class an Age property, by adding a Public variable to the Declarations section:
Option Explicit
Public Age As Double
The Procedure drop downs in the code modules for the Tyrannosaur and Flea classes now contain property procedures for implementing the Age property,

…

Using a public variable to implement a property is strictly a convenience for the programmer. Behind the scenes, Visual Basic implements the property as a pair of property procedures.

You must implement both procedures. The property procedures are easily implemented by storing the value in a private data member, as shown here:
Private mdblAge As Double

Private Property Get Animal_Age() As Double
   Animal_Age = mdblAge
End Property

Private Property Let Animal_Age(ByVal RHS As Double)
   mdblAge = RHS
End Property
The private data member is an implementation detail, so you have to add it yourself.

也就是说，“公共接口”无论您使用公共变量还是使用Property Get/Let定义，它们都是完全相同的。要在接口中实现属性，您不能使用公共变量方法，而需要使用Property Get/Let语法并在自己的私有变量中处理数据存储。