Overloading Properties

Question

I tried to overload in VBA within a class module:

Dim a As Integer

Public Property Let SomeNumber(newNumber as Integer)
   a = newNumber
End Property
Public Property Let SomeNumber(newNumber as String)
   a = Val(newNumber)
End Property
Public Property Get SomeNumber() As Integer
   SomeNumber = a
End Property

The compiler complains that an "ambiguous name was detected" where clearly there is a different signature. Is it possible to overload a property defined within a class in VBA or VB6? If so, what would be the syntax?

Moreover, if property overloading is not possible, what benefits do properties offer over get/set methods defined by public functions other than a more seamless way to access the fields of an instantiated object?

I'm pretty sure you can't, but I'll let someone who's 100% sure answer. — Lance Roberts, Mar 09 '11 at 20:05

score 2 · Answer 1 · answered Mar 09 '11 at 20:34

2

Can you use a variant or object type and manually handle the type checking?

A mixture of Optional parameters may also be possible, but it's not exactly equivalent to overloading either.

answered Mar 09 '11 at 20:34

Enull

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score 2 · Answer 2 · answered Mar 11 '11 at 12:21

No.

The workaround is to use Variants, which allows the client to pass anything. But you have to write code to do the type-checking at runtime:

Public Property Let SomeNumber(newNumber as Variant)
   Select Case VarType(newNumber) 
      Case vbInteger         '' Caller passed an integer
        a = newNumber
      Case vbString          '' Caller passed a string
        a = Val(newNumber)
      Case Else
        Err.Raise vbObjectError+513, , "Invalid type passed"
      End Select
End Property
Public Property Get SomeNumber() As Variant
   SomeNumber = a
End Property

For more details see Dan Appleman's excellent book Developing COM/ActiveX Components In Visual Basic 6.

score 1 · Accepted Answer · answered Mar 09 '11 at 20:20

1

From what I can see here:

http://vbcity.com/forums/t/76453.aspx

It seems you are out of luck until you convert to VB.NET.

answered Mar 09 '11 at 20:20

AZhu

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score 1 · Answer 4 · edited May 23 '17 at 09:58

1

There was a thread on this topic:

Function Overloading and UDF in Excel VBA

edited May 23 '17 at 09:58

Community

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1

answered Mar 09 '11 at 20:21

MPękalski

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This is a similar thread, but not quite what I was looking for. Still good insight thought. – Chad Harrison Mar 09 '11 at 20:30

Overloading Properties

4 Answers4