Variable number of arguments in VB

Question

How to create a function with variable number of arguments in visual basic? ex.

x =  Sum(1,2,3)
y =  Sum(1,2)

Function Sum('how to declare argument here')
'Is there any special argument manipulation inside function before it is usable?
End Function

score 25 · Accepted Answer · edited Apr 13 '10 at 16:09

25

Have a look at Passing a Variable Number of Arguments

Function Sum(ParamArray Vals() As Variant)
    Dim intLoopIndex As Integer
    For intLoopIndex = 0 To  UBound(Vals)

    Next intLoopIndex

End Function

edited Apr 13 '10 at 16:09

MarkJ

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answered Apr 13 '10 at 14:18

Adriaan Stander

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Will this also work on VBA? I tried it on VBA but it is not working. It can't recognize ParamArray – Kratz Apr 13 '10 at 14:41
1

The code above has the right idea, but won't compile as-is. 1) A `ParamArray` can't be declared `ByVal` and 2) it can only be declared as a `Variant` array. Therefore, the function declaration should be `Function Sum(ParamArray Vals() As Variant)` – Mike Spross Apr 13 '10 at 14:48
@ Mike Spross: It works based on the rules you stated. Thanks. @ astander: thanks for the heads up. – Kratz Apr 13 '10 at 14:55
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@Mike Spross, @Katz, @astander I have taken the liberty of editing astander's answer to correct the syntax. Mike was quite right about the changes needed. (Also +1 to Arvo who has also suggested optional arguments) – MarkJ Apr 13 '10 at 16:11

score 12 · Answer 2 · answered Apr 13 '10 at 14:20

12

Use optional arguments, like:

Function Sum(Optional X1 As Integer=0, Optional X2 As Integer=0)

or universally variable arguments syntax

Function Sum(ParamArray XArr() As Variant)

(I may have messed with some syntax elements - feel free to correct.)

answered Apr 13 '10 at 14:20

Arvo

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score 4 · Answer 3 · answered Aug 29 '14 at 04:36

The answers here are great. In my application I required an arbitrarily long list of optional arguments after a required initial argument.

You can do this by simply adding the required arguments before the ParamArray entry.

For example:

Function Arithmetic(FuncType As String, ParamArray Terms() As Variant)

Variable number of arguments in VB

3 Answers3

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