在 VBA 中定义一个函数别名，可能吗？
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define a function alias in VBA, possible?
提问by orshachar
I am using VBA behind MS Access Say I have global methods foo1 and foo2 that gets the same arguments but do different things. I know that in C++ I can assign a function an alias. Something like: instead of:
我在 MS Access 后面使用 VBA 假设我有全局方法 foo1 和 foo2，它们获取相同的参数但做不同的事情。我知道在 C++ 中，我可以为函数分配别名。类似于：而不是：
If (term) then
foo1 arg1, arg2, arg3
else
foo2 arg1, arg2, arg3
End If
I want to write:
我想写：
Var new_func = Iff (term, foo1,foo2)
new_func arg1, arg2, arg3
Can I do this on vba?
我可以在 vba 上做这个吗？
回答by Fionnuala
Would Run suit?
跑步适合吗？
new_func = IIf(term, "foo1", "foo2")
''new_func arg1, arg2, arg3
res = Run(new_func, "a", "b", 1)
More information: http://msdn.microsoft.com/en-us/library/aa199108(office.10).aspx
更多信息：http: //msdn.microsoft.com/en-us/library/aa199108(office.10).aspx
回答by Alex K.
If the 2 functions were implemented in 2 different class modules you could give them the same name & call them across an interface. That's about as close as you can get. (and its not very close)
如果这 2 个函数是在 2 个不同的类模块中实现的，您可以为它们指定相同的名称并通过接口调用它们。这几乎是你所能得到的。（而且它不是很接近）
'empty interface class, name: IFoo
Public Function TheFunc(i As Integer) As Long
'
End Function
'class clsFoo1
Implements IFoo
Private Function IFoo_TheFunc(i As Integer) As Long
MsgBox "I'm clsFoo1"
End Function
'class clsFoo2
Implements IFoo
Private Function IFoo_TheFunc(i As Integer) As Long
MsgBox "I'm clsFoo2"
End Function
'module code;
Dim myFoo As IFoo
If var = 1 Then
Set myFoo = New clsFoo1
Else
Set myFoo = New clsFoo2
End If
myFoo.TheFunc 12345
回答by Tom Juergens
No, unfortunately, that's not possible with VBA. Would be nice, but you'll just have to stick to your first syntax.
不，不幸的是，这在 VBA 中是不可能的。会很好，但你只需要坚持你的第一个语法。
Update: So, I stand by my original assertion that the construct proposed in the question does not exist in VBA, but Alex K.and Remouhave provided usable workarounds.
更新：所以，我坚持我最初的断言，即问题中提出的构造在 VBA 中不存在，但Alex K.和Remou提供了可用的解决方法。
回答by Mark Mayo
Try this:
尝试这个：
http://oreilly.com/catalog/vbanut/chapter/booklet.html#sect5
http://oreilly.com/catalog/vbanut/chapter/booklet.html#sect5
The AddressOfoperator.
该AddressOf运营商。
However as noted on http://discuss.fogcreek.com/joelonsoftware4/default.asp?cmd=show&ixPost=140196&ixReplies=19
但是，如http://discuss.fogcreek.com/joelonsoftware4/default.asp?cmd=show&ixPost=140196&ixReplies=19 所述
"AddressOf is really a cheap hack. VB doesn't support first-class function values like most other languages, but with AddressOf is supports it halfway. Yes you can get the address of a function but you can't invoke a function by address (unless that function is a message processor and only then with the Win32 function CallWndProc). All you can do to simulate this behavior is take generic dispatch objects instead of function pointers and ensure that the objects support the necessary functions. "
“AddressOf 确实是一个廉价的hack。VB 不支持像大多数其他语言一样的一流函数值，但是AddressOf 是支持它的一半。是的，您可以获得函数的地址，但不能通过地址调用函数（除非该函数是消息处理器，并且只有使用 Win32 函数 CallWndProc 才能模拟此行为。您所能做的就是采用通用调度对象而不是函数指针，并确保这些对象支持必要的功能。”
Unfortunately, that's about as close as you'll get, I believe.
不幸的是，我相信这几乎是你所能得到的。
For more info on AddressOf, see here.
有关更多信息AddressOf，请参见此处。
回答by Sancarn
I realise this is an old question, but I suggest using STD.Types.Callbackwhich is part of my VBA library.
我意识到这是一个老问题，但我建议使用STD.Types.Callback，它是我的 VBA 库的一部分。
Usage:
用法：
sub test()
Dim msg as STD_Types_Callback
set msg = STD.Types.Callback.Create("Module","Module1","Msg")
'or
'set msg = STD.Types.Callback.Create("Object",myObject,"Msg")
DoMessage(msg, "hello world") '=> "hello world"
end sub
function Msg(message)
Msgbox message
end function
function DoMessage(a as object, b as string)
a(b)
end function
