User Defined Types and Classes

Any way to set the property of a User Defined Type that's a property of a class?

For example:

Type XandY 'Global type
X As Long
Y As Long
End Type

Class SomeClass
Private c_Pos As XandY

'[Property Let called "Pos" that edits c_Pos goes here]

'And then execute this code:

Dim Instance As New SomeClass
Instance.Pos.X = 3

Can this be done at all using a Property Let/Set Procedure?

In my experience objects in VB6 are slow and ugly.
If you are trying to make some sort of vector graphics tool I would not use objects at all

Use nested UDTs or move to VB.NET. (Much more robust in graphics.)

~T

Can this be done at all using a Property Let/Set Procedure?

Sure, you can do that one of two ways. Either expose a property Let for X and Y separately, or make a single XandY property. Note that Type XandY must be defined as public in a BAS module.


' Class code
Public Property Let X(ByVal lX As Long)
c_Pos.X = lX
End Property

Friend Property Let Pos(ByRef tPos As XandY)
c_Pos = tPos
End Property



' Usage
Private Sub Form_Load()
Dim tXY As XandY
Dim c As Class1
Set c = New Class1

tXY.X = 42
tXY.Y = 123
c.Pos = tXY

' Or
c.X = 42
End Sub

Thanks for the help. That wasn't the exact functionality I wanted, but I guess that's not possible.

Friend Property Let Pos(ByRef tPos As XandY)
c_Pos = tPos
End Property
This errored for me until I realized the name had to be different than a corresponding Get Property.

In my experience objects in VB6 are slow and ugly.
If you are trying to make some sort of vector graphics tool I would not use objects at all

Use nested UDTs or move to VB.NET. (Much more robust in graphics.)

I was actually trying to construct a class for a file format, so that cleanup and re-initialization of variables would be easier.

You asked for a UDT, so that's as close as you get. It is also possible with a class.


' begin cPos.cls
Option Explicit

Private m_lX As Long
Private m_lY As Long

Public Property Let X(ByVal lX As Long)
m_lX = lX
End Property

Public Property Get X() As Long
X = m_lX
End Property

Public Property Let Y(ByVal lY As Long)
m_lY = lY
End Property

Public Property Get Y() As Long
Y = m_lY
End Property



' begin Class1.cls
Option Explicit

Public Pos As cPos

Private Sub Class_Initialize()
Set Pos = New cPos
End Sub



' Usage:
Private Sub Form_Load()
Dim c As Class1
Set c = New Class1

c.Pos.X = 42
End Sub

This errored for me until I realized the name had to be different than a corresponding Get Property.

Name had to be different? Both the Let and Get would be named Pos. Do you mean the variable name?

Name had to be different? Both the Let and Get would be named Pos. Do you mean the variable name?

I had a Get property return a UDT and it worked fine, but the Let property errored when I tried to make it accept a UDT. Something about invalid last parameter. It fixed when I made it a Friend and named it something else, as you suggested.