Re: Incorporating optional function argument

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Thanks for looking into it. It's something to try in the future if needed, I suppose, but I wish I had a better understanding of why an "optional" argument is requireed in some cases. For now I have added the optional argument to the event property function calls.

"JString" <JString@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message news:5A180EA5-37FF-4AAC-8C90-CE8C4C2975C8@xxxxxxxxxxxxxxxx
I can't answer your question as to why this occurs or where it might be
documented, but I may have found a solution for your problem.

I found that if I have the function located in the form's module, all
parameters are required for it to work correctly, including optional ones.
However, after moving the function to a new module, it worked even if the
optional parameter was left blank in the event property.

"BruceM" wrote:

I don't see that the code you used calls for anything to happen that the
user can see or otherwise verify. If, for instance, you had MsgBox =Test or
Debug.Print Test there would be something for the user to observe.

Adding a message box to your code, and removing blnVal from the value
returned by the function:
Public Function test(strMsg As String, Optional blnVal As Boolean = False)
test = strMsg
MsgBox test
End Function

If I put this into the event property (After Update for a combo box),
nothing happens:
=test("this is a test ")

The function does not even start. A break point at the Public Function line
does not result in the code breaking. However, this works:
=test("this is a test ", False)

In VBA code, a function call works whether or not there is an optional
argument. Both of these work if I put them into After Update code:

test("this is a test ")
test("this is a test ", False)

Nothing changes if I add something for blnVal to do:
Public Function test(strMsg As String, Optional blnVal As Boolean = False)
test = strMsg
MsgBox test
Me.SomeControl.Visible = blnVal
End Function

If it is syntax, the syntax for a function call from an event property is
different from the syntax for a function call in code, but in a way that
seems not to be documented.

"JString" <JString@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:B9F4FC72-BC13-459D-9DEA-34EDED423174@xxxxxxxxxxxxxxxx
> That's pretty strange that you were able to get it to work at all. I
> tried
> reproducing your scenario with this code:
>
> Public Function test(strMsg As String, Optional blnVal As Boolean = > False)
> test = strMsg & blnVal
> End Function
>
> I then assigned the OnClick property of a textbox to :
>
> =test("this is a test ", False)
>
> And nothing happened. However, other variations gave me an error > stating
> that a macro by this name couldn't be found.
>
> The VBA help file for the OnClick property states that it can be used > to
> programmatically change the behavior of a control object from an event
> procedure to a macro or vice versa. So perhaps it's a syntax issue, if
> I'm
> understanding you correctly.
>
>
>
> "BruceM" wrote:
>
>> After much searching online I have found some information in VBA Help
>> about
>> using optional arguments in a user-defined function, but I cannot find
>> anything to find why adding an optional argument would make the >> function
>> stop working when I call it from the event property. Here are some
>> details,
>> in case my terminology is unclear.
>>
>> The function builds a filter string that is used to filter the >> recordset.
>> It works as it should. However, in one instance I need a modified
>> approach
>> when making a selection from one of the combo boxes that is used to
>> select
>> the elements of the filter. Here is the function title (or whatever >> it's
>> called):
>>
>> Public Function SelFilter(lngID As Long) As String
>>
>> On the Property *** for a combo box I have the following for the >> After
>> Update event:
>> =SelFilter([cboFind])
>>
>> In other cases the function is called in code (because the event has >> to
>> do
>> several things).
>>
>> My idea was to add an optional boolean to the function:
>> Public Function SelFilter(lngID As Long, Optional blnSel as Boolean) >> As
>> String
>> or
>> Public Function SelFilter(lngID As Long, Optional blnSel as Boolean =
>> False)
>> As String
>>
>> From what I can tell, this works only if I am calling the function >> from
>> code. That is, in an event procedure I can have:
>>
>> SelFilter(Me.cboFind, False)
>> or
>> SelFilter(Me.cboFind)
>>
>> Either one works.
>>
>> However, on the property ***, this doesn't even call the function:
>> =SelFilter([cboFind])
>> I put a break point at the function title, but the code never ran.
>> However,
>> when I did this:
>> =SelFilter([cboFind], False)
>> The function worked.
>>
>> What I am getting from this is that optional arguments cannot be left
>> blank
>> when calling the function from the property ***. In other words, >> all
>> arguments, even optional ones, are required when calling the function
>> from
>> the property ***. If this is documented I cannot find it.
>>
>> I am using Access 2003.
>>
>>



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