如何动态引用VBA中的对象属性

Question

我正在尝试编写一个VBA函数，该函数可以根据对象的某个属性的值来计算集合中的对象。我需要被检查的对象属性是动态的，由函数参数提供。我可以使用if then声明，但是这将有许多很多elseif子句，每个子句都具有相同的过程，但属性名称除外。

我想避免重复我的代码重复每个属性的名称。这是迄今为止我所拥有的。

Private Function getTicketCount(c As Collection, f As String, s As String) _ 
As Long 
' @param c: collection of Ticket objects. 
' @param f: property to filter. 
' @param s: filter string. 
' 
' Function returns number of tickets that pass the filter. 

Dim x As Long 
Dim t As Ticket 

x = 0 

For Each t In c 
    If t.f = s Then x = x + 1 ' Compiler throws "Method or data member not found." 
Next t 

getTicketCount = x 
End Function 

我遇到的问题是编译器正在寻找t的“f”属性而不是t的f值属性。确切的错误在上面的代码块中注释。我如何使用f的值而不是“f”来引用对象属性？

Answer 1

我相信你想使用CallByName方法CallByName MSDN Link

Private Function getTicketCount(c As Collection, f As String, s As String) _ 
As Long 
' @param c: collection of Ticket objects. 
' @param f: property to filter. 
' @param s: filter string. 
' 
' Function returns number of tickets that pass the filter. 

Dim x As Long 
Dim t As Ticket 

x = 0 

For Each t In c 
    If CallByName(t, f, VbGet) = s Then x = x + 1 ' Compiler throws "Method or data member not found." 
Next t 

getTicketCount = x 
End Function