CODEWITHSUNDEEP
c#vb6
JMK
JMK

Reputation: 28059

Optional Parameters with default values in VB6

I am trying to recreate the following C# code in VB6:

private void ChangeTab(string tabName, bool clearAll = true)
{
    Yadyyada(tabName);

    if (clearAll)
    {
        DoMoreStuff();
    }
}

Here is what I have so far:

Private Sub ChangeTab(ByVal tabName As String, Optional ByVal clearAll As Boolean)

    Yadyyada(tabName)

    If clearAll = True Then
        DoMoreStuff
    End If

End Sub

So far so good apart from the default parameter. Can I assign clearAll a default value of true in the method signature in the same way I can in C# or do I just need to do this at the start of the method?

Thanks

Upvotes: 1

Views: 2511

Answers (4)

Gustavo Fuentes
Gustavo Fuentes

Reputation: 86

You can use IsMissing Function like this

Private Sub ChangeTab(ByVal tabName As String, Optional ByVal clearAll As Boolean)

    Yadyyada(tabName)

    If IsMissing(clearAll) = True Or clearAll = True Then
        DoMoreStuff
    End If

End Sub

My Mistake! Setting a default true value for optional parameter and check for this in code is the best solution!

Private Sub ChangeTab(ByVal tabName As String, Optional ByVal clearAll As Boolean = True)

    Yadyyada(tabName)

    If clearAll = True Then
        DoMoreStuff
    End If

End Sub

Upvotes: 0

Steve
Steve

Reputation: 216243

Yes, you could do the same thing as in C#

Private Sub ChangeTab(ByVal tabName As String, Optional ByVal clearAll As Boolean = True) 
    Debug.Print "Value for clearAll=" & clearAll
End Sub

calling with

ChangeTab("AName")

will print True

Upvotes: 4

Tomek Szpakowicz
Tomek Szpakowicz

Reputation: 14502

Try:

Private Sub ChangeTab(ByVal tabName As String, Optional clearAll As Boolean = True)

    Call Yadyyada(tabName)

    If clearAll Then
        DoMoreStuff
    End If

End Sub

See http://msdn.microsoft.com/en-us/library/aa266305%28v=vs.60%29.aspx

Upvotes: 2

Simon Whitehead
Simon Whitehead

Reputation: 65049

Wow this takes me back.. can I ask why you're converting backwards technology-wise?

Anyway, you can use the Optional keyword:

Private Sub ChangeTab(ByVal tabName As String, Optional ByVal clearAll As Boolean = True)

Your issue is using ByVal. From memory, everything in VB6 was ByVal unless explicitly stated.

EDIT: I'm wrong. Default was ByRef.. it's been so long!

Upvotes: 9

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