Found and Set Value to a UDT member VB6

Question

I'm looking for some help to solve a problem with dynamic set values of the UDT members. I'm trying do something like the pseudocode ahead:

Public sub UDTMemberSetValue(ByRef pvUDTValue As Variant, _
                             ByVal psMemberName As String, _
                             pvMemberValue As Variant)
    Dim mMember as Member

    For each mMember in pvUDTValue.Members
        if mMember.Name = psMemberName then
            if isObject(pvMemberValue) then
                Set mMember.Value = pvMemberValue
            else
                mMember.Value = pvMemberValue
            End if
        End If
    Next
End Sub

I've been searched several sites, unfortunately no one of them, got near of my necessity. So I'd like know if someone could help me with this?

Answer 1

You can't do this in straight VB6. However, you can use the tlbinf32.dll ActiveX component, which is installed as part of Windows since at least Windows XP. This can be used to extract information about Classes, Interfaces and Records (i.e. UDTs) from type libraries. The downside is that if you want to use this with VB UDTs, it will only work if your UDT is declared Public in a Publically exposed VB Class or UserControl.

The component should be registered; but if it isn't, use regsvr32.exe tlbinf32.dll. It should appear in your list of References as TypeLib Information, and has library name TLI.

I have modified your pseudo-code to include the library. The original version of this was so like your code, I was wondering whether you knew this already.

But there is a simpler way that iterating through the member info, and setting the value property of the correct one: use the RecordField property. Unfortunately, at least on my machine, I couldn't pass pvUDTValue directly into this property. But after trial and error, I discovered that it worked with a copy of the variant. You just have to remember to replace the original variant with the copy after updating the field.

Public Sub UDTMemberSetValue(ByRef pvUDTValue As Variant, _
                             ByVal psMemberName As String, _
                             ByRef pvMemberValue As Variant)
    Dim oApp            As TLI.TLIApplication
    Dim vTemp           As Variant

    Set oApp = New TLI.TLIApplication

    vTemp = CVar(pvUDTValue)
    oApp.RecordField(vTemp, psMemberName) = pvMemberValue
    pvUDTValue = vTemp

End Sub