Charlotte Foust
cfoust at infostatsystems.com
Fri May 25 11:20:31 CDT 2007
Oops! Make that the AndAlso operator <blush>. That's what I get for
multitasking!
If Not addrRow.IsMAddress2Null AndAlso addrRow.MAddress2.Trim.Length >
0 Then
Charlotte
-----Original Message-----
From: dba-vb-bounces at databaseadvisors.com
[mailto:dba-vb-bounces at databaseadvisors.com] On Behalf Of Charlotte
Foust
Sent: Friday, May 25, 2007 7:52 AM
To: dba-vb at databaseadvisors.com
Subject: Re: [dba-VB] Checking for NULL and empty strings
And once you have tested the IsNull, you can use the OrElse operator to
check for an empty string like this:
If Not addrRow.IsMAddress2Null OrElse addrRow.MAddress2.Trim.Length > 0
Then
The AndAlso and OrElse operators are a treasure because they only
evaluate that part of the expression if the first part succeeds.
Charlote Foust
-----Original Message-----
From: dba-vb-bounces at databaseadvisors.com
[mailto:dba-vb-bounces at databaseadvisors.com] On Behalf Of Charlotte
Foust
Sent: Friday, May 25, 2007 7:32 AM
To: dba-vb at databaseadvisors.com
Subject: Re: [dba-VB] Checking for NULL and empty strings
If you're using a typed dataset, string and some other data types have
an Is<FieldName>Null property that you can test. Cast the record as a
row of the appropriate datatype to use it. Then you should be able to
use something like addrRow.IsMAddress2Null to check it.
Charlotte Foust
-----Original Message-----
From: dba-vb-bounces at databaseadvisors.com
[mailto:dba-vb-bounces at databaseadvisors.com] On Behalf Of David Emerson
Sent: Thursday, May 24, 2007 5:52 PM
To: dba-vb at databaseadvisors.com
Subject: Re: [dba-VB] Checking for NULL and empty strings
Thanks David,
I originally had a similar syntax but was hoping that there was an
shorter method.
David
At 25/05/2007, you wrote:
>Here's a function I wrote (actually I wrote it for C#, but crossed it
>over to vb.net)
>
> Public Function IsNull(ByVal strInput As String, ByVal strReplace
>As
>String) As String
> 'This works like SQL server's IsNull, not VB/VBA. In VB/VBA it
>is known as Nz()
> If (strInput Is Nothing) Then
> Return strReplace
> Else
> If strInput = "" Then
> Return strReplace
> Else
> Return strInput
> End If
> End If
> End Function
>
>
>On 5/24/07, David Emerson <newsgrps at dalyn.co.nz> wrote:
> >
> > Group,
> >
> > I am wanting to test the value of a field from a data source. If it
> > is NULL or "" then do one thing, otherwise do another. Here is
> my vb.netcode:
> >
> > If IsDBNull(Fields("MAddress2").Value) Or
> > (Fields("MAddress2").Value = "") Then
> > Me.txtMailAddress.DataField = "=MAddress1"
> > Else
> > Me.txtMailAddress.DataField = "=MAddress1" + Chr(34) +
> > ", " + Chr(34) + " + MAddress2"
> > End If
> >
> > The error message is "
> >
> > Operator '=' is not defined for type 'DBNull' and string "".
> >
> > What is the correct syntax for this?
> >
> >
> > Regards
> >
> > David Emerson
> > Dalyn Software Ltd
> > Wellington, New Zealand
> > _______________________________________________
> > dba-VB mailing list
> > dba-VB at databaseadvisors.com
> > http://databaseadvisors.com/mailman/listinfo/dba-vb
> > http://www.databaseadvisors.com
> >
> >
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