John Colby
jcolby at colbyconsulting.com
Mon Oct 20 03:02:24 CDT 2003
I try and avoid variants as well. Unfortunately IsMissing requires a
variant. In this sort of application it appears to me that using a variant
is worthwhile to avoid the issue of "what is a valid 'not used' value" and
will that value be "not used" tomorrow.
John W. Colby
www.colbyconsulting.com
-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com]On Behalf Of Stuart Sanders
Sent: Monday, October 20, 2003 3:37 AM
To: 'Access Developers discussion and problem solving'
Subject: RE: [AccessD] A2K Reference the dot column property in a query
Yes ... You can't set variables declared as LONG/INTEGER/STRING etc as null.
Ie
DIM lngi as LONG
Lngi = NULL
This won't work ... It will generate an error. You can only do that with
variants. I usually try to avoid variants, so would use something like
this:
STATIC FUNCTION StartDate(OPTIONAL dteStartDate as Date = 0) as Date
Local dteStore as Date
IF dteStartDate <> 0 Then
dteStore = dteStartDate
END IF
StartDate = dteStore
End FUNCTION
Of course this assumes that 00:00:00 Jan 1 1890 (or whenever the start value
of
the date variable is) is not going to be a valid input.
In some circumstances I add initialisation options.
Stuart
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of John Colby
> Sent: Monday, 20 October, 2003 3:16 PM
> To: Access Developers discussion and problem solving
> Subject: RE: [AccessD] A2K Reference the dot column property
> in a query
>
>
> Arthur,
>
> The only way I was able to get this working was using an
> optional VARIANT
> and checking IsMissing. IsNull didn't work on a missing integer.
>
> Static Function FltrSfrmClaimAssociatesCboContactSelFilter(Optional
> llngCTYID As Variant)
> Dim lngCTYID As Variant
> If Not IsMissing(llngCTYID) Then
> lngCTYID = llngCTYID
> End If
> FltrSfrmClaimAssociatesCboContactSelFilter = lngCTYID
> End Function
>
> It does work great though. Set it up to be called in
> AfterUpdate of the
> filter combo and used the function value in the dependent
> combo's query.
>
> John W. Colby
> www.colbyconsulting.com
>
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com]On Behalf Of
> Arthur Fuller
> Sent: Saturday, September 06, 2003 2:49 PM
> To: Access Developers discussion and problem solving
> Subject: RE: [AccessD] A2K Reference the dot column property
> in a query
>
>
> Thanks for the explication, Stuart!
>
> IMO the coolest thing about statics is that you can eliminate
> references to
> forms. In the AfterUpdate event of some control, you call the static
> function and pass the param. Anywhere else you need it, call the func
> without a param. I don't like being tied to particular forms
> being open. I
> want to be able to run a query etc. from the debug window
> anytime I want,
> and to set said static func from the debug window anytime I
> want. Statics
> give me this. That's why I love 'em.
>
> A.
>
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com]On Behalf Of
> Rocky Smolin -
> Beach Access Software
> Sent: Saturday, September 06, 2003 8:23 AM
> To: Access Developers discussion and problem solving
> Subject: Re: [AccessD] A2K Reference the dot column property
> in a query
>
>
> Oh. That's very cool.
>
> Rocky
>
> ----- Original Message -----
> From: "Stuart McLachlan" <stuart at lexacorp.com.pg>
> To: "Access Developers discussion and problem solving"
> <accessd at databaseadvisors.com>
> Sent: Friday, September 05, 2003 5:40 PM
> Subject: Re: [AccessD] A2K Reference the dot column property
> in a query
>
>
> > On 5 Sep 2003 at 7:48, Rocky Smolin - Beach Access S wrote:
> >
> > > Must have missed that thread Arthur. What are static functions?
> > >
> >
> >
> > Functions which retain the value of their variables between calls.
> > Something like:
> >
> > STATIC FUNCTION StartDate(OPTIONAL dteStartDate as Date) as Date
> > Local dteStore as Date
> > IF NOT ISNULLl(dteStartDate) Then
> > dteStore = dteStartDate
> > END IF
> > StartDate = dteStore
> > End FUNCTION
> >
> > Every time you call the function with a date parameter, it sets its
> > value. Every time you call it without a parameter, it returns the
> > last value set.
> >
> > You can now you user select a start date on a "pick form"
> somewhere.
> > When they have picked it, set the value of Startdate() with
> > something like dteTemp = StartDate(txtStartDate)
> >
> > Now you can use "=StartDate()" in reports, queries, form filters etc
> > anywhere you like. It will return the selected value until the user
> > goes back to the pick form and changes it.
> >
> >
> >
> > --
> > Lexacorp Ltd
> > http://www.lexacorp.com.pg
> > Information Technology Consultancy, Software
> Development,System Support.
> >
> >
> >
> > _______________________________________________
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> > Website: http://www.databaseadvisors.com
> >
>
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