Tim Tim - 1 year ago 258
Vb.net Question

VB.Net - Using a subclass in a class

Trying to convert some VBA code to VB.Net and getting hung up on some class issues. I have a main class: clsComputer. It has a subclass: clsHardDrive. Since a computer can have more than 1 hard drive, it's

properties look like this in clsComputer:

Private pHardDrive(8) As clsHardDrive

Public Property Get HardDrive(index As Integer) As clsHardDrive
If pHardDrive(index) Is Nothing Then Set pHardDrive(index) = New clsHardDrive
Set HardDrive = pHardDrive(index)
End Property
Public Property Set HardDrive(index As Integer, value As clsHardDrive)
pHardDrive(index) = value
End Property

This allows me to do something like this in code:

objComp.HardDrive(0).Size = "500"
objComp.HardDrive(1).Size = "1000"

However, I don't know how to convert this to VB.Net. I tried this:

Property HardDrive As HDD
Get (ByVal index As Integer)
Return pHardDrive(index)
End Get
Set (ByVal index As Integer, value As HDD)
pHardDrive(index) = value
End Set
End Property

But it gives a compile error:
Property without a 'ReadOnly' or 'WriteOnly' specifier must provide both a 'Get' and a 'Set'. (BC30124)

Searching that error isn't very helpful:
To correct this error make sure you include both a Get procedure and a Set procedure between the Property statement and the End Property statement.
I have both Get and Set, and I think they are properly terminated. I've also searched for examples on using one class within another, but I didn't find anything useful.

How do I get the same functionality in VB.Net that I have in VBA? EG, how do I create the instances of HardDrive so that one computer object can have many hard drive objects?

Answer Source

Indexed properties still exist in VB.NET, just like classic COM-based VB.

You just have the syntax wrong. Indexed properties really just a special case of a parameterized property, so the index is taken as a parameter for the entire property, not the individual Get and Set statements.

Public Class Computer

    Private m_hardDrives(8) As HDD

    Public Property HardDrive(ByVal index As Integer) As HDD
            Return m_hardDrives(index)
        End Get
        Set(ByVal value As HDD)
            m_hardDrives(index) = value
        End Set
    End Property

End Class
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