VBA - 使用类的文本名称创建一个新对象 [英] VBA - Create a new object using the text name of the class

问题描述

有没有办法通过使用类的文本名称将对象设置为类的新实例？

Is there a way to set an object to the new instance of a class by using the text name of the class?

我将有一个类库，并且根据一些其他变量，我想在运行时得到这些类之一。

I will have a library of classes, and depending on some other variable, I want to get one of these classes at runtime.

例如我有CTest1，CTest2，CTest3

E.g. I have "CTest1", "CTest2", "CTest3"

我的功能类似于以下

Function GetTestClass(lngClassNo as long) as Object

 Dim strClassName as String    
 strClassName = "CTest" & CStr(lngClassNo)

 Set GetTestClass = New instance of class(strClassName)

End Function

推荐答案

VBA中没有反思，所以我不认为这是可能的。你必须像下面那样做一些类似的事情：

There's no reflection in VBA, so I don't think this is possible. You'd have to do something like the following I'm afraid:

Function GetTestClass(lngClassNo as long) as Object

    Select Case lngClassNo
    Case 1
        Set GetTestClass = New CTest1
    Case 2
        Set GetTestClass = New CTest2
    ...

    End Select

End Function

除非是您的CTest类在COM DLL中定义，在这种情况下，您可以使用CreateObject语句。您将需要使用VB6创建这样一个DLL，但不能在Excel，Access等中创建DLL。

Unless that is your CTest classes are defined in a COM DLL, in which case you could use the CreateObject statement. You would need to use VB6 to create such a DLL though, you can't create DLLs in Excel, Access, etc.

Function GetTestClass(lngClassNo as long) as Object

    Set GetTestClass = CreateObject("MyDll.CTest" & lngClassNo)

End Function

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