Class Object update using a form - forms

Question

I am creating a tool in VBA to create labels with information about transactions.
I would like the user to use a form to give all the information and the labels will be automatically created.
To do so I have created a transaction class called clsTransaction.
Public PartNum As String
Private Sub Class_Initialize()
MsgBox "initialized!"
End Sub
At the initilalisation of the form a new object is created
Private Sub UserForm_Initialize()
(...)
Dim trans As New clsTransaction
End Sub
Then when a textbox is updated, I want to update the object property
Private Sub txtPartNum_AfterUpdate()
Dim strPartNum As String
strPartNum = txtPartNum.Value
MsgBox (strPartNum)
trans.PartNum = strPartNum
End Sub
I get the following error message
Run-time error '424':
Object required
My understanding is I need to declare the obect. I have tried to add:
dim trans as object
but I get an other error message:
Run time error '91':
object variable or With block variable not set
Could someone help me to update the object through the form?

Answer 1

The problem seems to be in the scope of your declaration. By doing this:
Private Sub UserForm_Initialize()
(...)
Dim trans As New clsTransaction '<-- declaration + assignment
End Sub
you are declaring trans in the scope of UserForm_Initialize(). Hence, when you then try to do something with it into another scope:
Private Sub txtPartNum_AfterUpdate()
(...)
trans.PartNum = strPartNum
End Sub
the object trans doesn't exist anymore because it's out of scope (so it has already been collected by the garbage collector) and you get an "object required error". You need to declare trans at global level, this is the idea:
Dim trans as yourClass '<-- global declaration: the object trans will keep on existing into all scopes
Private Sub UserForm_Initialize()
Set trans = New yourClass '<-- new instance of the object
End Sub
Private Sub txtPartNum_AfterUpdate()
'use the instance here
trans.PartNum = strPartNum
End Sub