You might have problems on a NewRecord since fields do not yet have a
value... you should also put your code on the control AfterUpdate event
so when the dependent value is changed, the code will also be executed

'~~~~~~~~~~~~~~~~~~~~~~
Private Sub Form_Current()
ShowHideApprBy
End Sub
'~~~~~~~~~~~~~~~~~~~~~~
Private Sub chkPaybackApproved_AfterUpdate()
ShowHideApprBy
End Sub
'~~~~~~~~~~~~~~~~~~~~~~
Private Sub ShowHideApprBy()
If Nz(Me.chkPaybackApproved, False) = True Then
Me.cboApprBy.Visible = True
Else
Me.cboApprBy.Visible = False
End If
end sub
'~~~~~~~~~~~~~~~~~~~~~~
in this case, if the control (field) does not yet have a value, False is
assumed


from Help
'~~~~~~~~~~~~~~~~~~~~~~~~~~``
Nz Function

You can use the Nz function to return zero, a zero-length string ("
"), or another specified value when a Variant is Null. For example, you
can use this function to convert a Null value to another value and
prevent it from propagating through an expression.

Syntax

Nz(variant[, valueifnull])

The Nz function has the following arguments.

Argument

variant
A variable of data type Variant.

valueifnull
Optional (unless used in a query).
A Variant that supplies a value to be returned if the variant
argument is Null. This argument enables you to return a value other than
zero or a zero-length string.

Note If you use the Nz function in an expression in a query without
using the valueifnull argument, the results will be a zero-length string
in the fields that contain null values.


'~~~~~~~~~~~~~~~~~~~~~~~~~~``

the thing to keep in mind when using Nz is what it will return if you
don't the specify the second, optional, argument.

If you are using Nz on a field, it will be the data type of that field
-- 0 for numbers (including dates), and an empty string for text or memo

Unbound textbox / combobox / listbox controls on a form are assumed to
have TEXT in them... so an empty string will be returned if nothing is
specified. And, if you specify something, it doesn't have to be 0 or ""

you could do this:

NZ(..., "no commision is found in the table for this employee")

If you do not specify the optional argument --
If the expression is bound to a text field, an empty string will be
returned if the field is null. If the expression is bound to a numeric
field, 0 will be returned if the field is null.

it is a good idea to wrap return values from dLookup, etc, in NZ in case
no match was found

.... a good "rule-of-thumb" is to specify the optional arguments (even
though it is not necessary)

for example:

= Nz(DLookup("[Commission]", "Employees"
, "[EmpID] = " & nz([EmpID],0)),0 )

notice how NZ is used twice -- once to make sure the criteria will be
evaluated, and another time around everything in case dLookup didn't
return a value...

Warm Regards,
Crystal

remote programming and training

Access Basics
8-part free tutorial that covers essentials in Access
http://www.AccessMVP.com/strive4peace

*
(: have an awesome day
*




GD wrote:
Can someone help me with some code? I need to create code that will make a
form's combo box visible or invisible, based on either a check box in the
form or its underlying table value (0 or -1). It also has to be record
specific, so I know I need to use CurrentRecord in there somewhere. This is
what I have, but it doesn't work.

Private Sub Form_Current()
If Me.chkPaybackApproved = True Then
Me.cboApprBy.Visible = True
Else
Me.cboApprBy.Visible = False
End If

End Sub

Does it need to be in another event? Note that I can't use AfterUpdate,
because I'm using a new form based on an older table, so the check boxes have
already been updated previously.

Thanks!!!