如何在Locals窗口中获取实现接口的类的属性值？ [英] How to get property values of classes that implement an interface in the Locals window?

问题描述

这真的困扰着我，阻碍了我的开发/调试。每当我声明我正在实现的接口的变量类型时，Locals Window都不会显示它的属性值。相反它只是读取

This is really bothering me and hindering my development/debugging. Whenever I declare a variable type of the interface I'm implementing, the Locals Window doesn't show it's property values. Instead it just reads

对象不支持此属性或方法

Object doesn't support this property or method

这很愚蠢，因为它确实如此。实际上 有 来履行与接口的合约。

Which is silly, because it absolutely does. In fact it has to in order to fulfill its contract with the Interface.

如果我将变量声明为该接口的具体实现，窗口按预期工作。但是，这完全违背了编码到抽象的目的。

If I declare the variable as the concrete implementation of the interface, the window works as expected. However, that completely defeats the purpose of coding to the abstraction to begin with.

如何让本地人窗口正确显示班级的属性值？

How can I get the locals window to properly display the class' property values?

最小，完整且可验证的示例：

创建 IClass 用作接口的类。

Option Explicit

Public Property Get Name() As String
End Property

创建 Class1 实现接口。

Option Explicit

Implements IClass

Public Property Get Name() As String
    Name = "Class1"
End Property

Private Property Get IClass_Name() As String
    IClass_Name = Name
End Property

最后，常规.bas模块中的一些测试代码用于说明问题。

And lastly, some test code in a regular .bas module to illustrate the issue.

Option Explicit

Public Sub test()
    Dim x As Class1
    Dim y As IClass

    Set x = New Class1
    Debug.Print x.Name

    Set y = New Class1
    Debug.Print y.Name

    Stop
End Sub

推荐答案

我可能错了，但我认为这可能是在VBA中实例化类的方式。

I could be wrong, but I think this may be something to do with the way classes are instantiated in VBA.

例如：

Dim oClass1 as Class1
Set oClass1 = new Class1

不同于

Dim oClass1 as New Class1

在第二种情况下，我认为在访问属性之前不会调用构造函数。

In the second case I believe the constructor doesn't get called until the property is accessed.

如果你试试这个，它会看到属性观察窗口。注意IClass的新功能 - 仅用于演示 - 我知道它不是这样做的方式:)

If you try this, it is sees the property in the Watch window. Notice the New for the IClass - just for Demonstration - I know its not the way to do that :)

Public Sub test1()

    Dim x As Class1
    Dim y As IClass

    Set y = New IClass
    Set x = New Class1
    Debug.Print x.Name
    Debug.Print y.Name
    Stop

End Sub

我怀疑它与此有关，观察窗需要这个......也许......

I suspect its something to do with that and the watch window requires this ... maybe...

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