Forms VBA Check Values to enable correct check boxes

[jlgray0127]

I have a form that I have 4 check boxes on.
By default, they are disabled. I want to check if there is a value in another text box to determine if the check box should be enabled. Simply stated, all I'm doing is checking for null. If null, remain disabled. If there is a value, enable = true.
The code kinda works, but is very inconsistent. Sometimes enabling or not enabling, when it should. I feel like I'm missing something. Any help is greatly appreciated!

Private Sub Form_Open(Cancel As Integer)
If [MakePartKit] >= 0 Then
MakeKit_Deliver.Enabled = True
End If

If [PFKit] >= 0 Then
PFKit_Deliver.Enabled = True
End If

If [LineSideKit] >= 0 Then
LinesideKit_Deliver.Enabled = True
End If

If [SubsKit] >= 0 Then
MadeSub_Deliver.Enabled = True
End If

End Sub

[Bob Fitz]

Perhaps:

MakeKit_Deliver.Enabled =Nz(Me.MakePartKit,0)>=0
PFKit_Deliver.Enabled =Nz(Me.PFKit,0)>=0
LineSideKit.Enabled =Nz(Me.LineSideKit,0)>=0
MadeSub_Deliver.Enabled =Nz(Me.SubsKit,0)>=0


in the forms OnCurrent event.

But what is the purpose of the checkbox controls?

[Welshgasman]

Why not use the IsNull() function?

[Bob Fitz]

Why not use the IsNull() function?

I can't think of any good reason not to use the IsNull() function. If I'd thought of it, I might even have suggested it

[Welshgasman]

I can't think of any good reason not to use the IsNull() function. If I'd thought of it, I might even have suggested it

Well O/P could combine it with your post?
Plus I posted that before seeing your post. It was addressed to the O/P

Me.ControlName.Enabled = NOT IsNull(Me.OtherControlName)

[June7]

Reason for instability possibly because Null cannot be compared to anything else because there is nothing to compare. However, expression of Null >=0 should be treated as a False result because it certainly can't return True.

Never build a comparison expression with equivalent operators when Null could be an input. Use IsNull(), Nz() or in SQL IS NULL.

Note suggestions using qualifier prefix of Me. Can wrap in With Me structure.

With Me
    .ControlName.Enabled = NOT IsNull(.OtherControlName)
...
End With

Could use With anyobjectreference to condense code.