This is equivalent to what I and a couple other suggested:
If FieldOfTypeDate = DBNull.Value Then
or in other words,
If myDataReader("MyFieldOfTypeDate") =
DBNull.Value Then
Are you saying this didn't work where
myDataReader.IsDBNull(ordinal)
did?
If you use the IsDBNull method, make sure you don't
hard-code the column
ordinal.
--Peter
> -----Original Message-----
> From: John Warner [mailto:john jwarner.com]
> Sent: Friday, June 15, 2007 9:19 AM
> To: aspnetaspadvice.com
> Subject: [aspnet] RE: VB.NET test for DBNull
>
>
> Thanks to all who have replied. After spending the
night in
> the docs (they
> get worse with each version of VS) I think I've found
the
> solution at least
> for a DataReader object. The dr method IsDBNull(column
> ordinal). This is
> supposed (I'm just back at my desk this morning) to
work for all the
> strongly typed dr.get<type> methods.
>
> John Warner
>
>
>
>
> > -----Original Message-----
> > From: lhoughrogers.com [mailto:lhoughrogers.com]
> > Sent: Friday, June 15, 2007 7:12 AM
> > To: aspnetaspadvice.com
> > Subject: [aspnet] RE: VB.NET test for DBNull
> >
> >
> > Try:
> >
> > If NOT myDataReader.item("Expr14") is
dbnull.value then
> >
> > HTH
> >
> > Larry
> >
> >
> > ----- Original Message ----
> > From: tom m <timallardmsn.com>
> > To: aspnetaspadvice.com
> > Sent: Friday, June 15, 2007 12:04:32 AM
> > Subject: [aspnet] RE: VB.NET test for DBNull
> >
> >
> > I've used a different syntax ... If
(myDataReader.Item("Expr14") =
> > System.DbNull.Value) Then ...
> >
> > tom mallard
> > .net web applications
> > consumer product design
> >
> > -----Original Message-----
> > From: Duane [mailto:starwaycorpcomcast.net]
> > Sent: Thursday, June 14, 2007 4:39 PM
> > To: aspnetaspadvice.com
> > Subject: [aspnet] RE: VB.NET test for DBNull
> >
> > If IsDBNull(myDataReader.Item("Expr14"))
Then 'checks if the
> > MapURL is Null
> >
> > 'do nothing
> > Else
> >
> > That should work for nulls in VB.NET
> >
> > htt
p://msdn2.microsoft.com/en-us/library/tckcces5(VS.80).as
px
> >
> >
> > -----Original Message-----
> > From: John Warner [mailto:johnjwarner.com]
> > Sent: Thursday, June 14, 2007 6:14 PM
> > To: aspnetaspadvice.com
> > Subject: [aspnet] RE: VB.NET test for DBNull
> >
> >
> > I thought I explained this, though not well
enough, the
> > Source is not SQL Server, it is not a file on any
computer I
> > can reach, it is an ODBC
> > (Transoft) data source on a Unix server. DTS will
not work,
> > it can't see the data source, I barely can. That
is why I was
> > asking about VB.NET solutions. I find it amazing
that
> > Microsoft knowing well over half the development
in VB or C#
> > is targeting databases and they provide no good
means to test
> > for NULL in .NET when once they did provide a
method.
> >
> > But thank you for trying.
> >
> > Any one ever have to deal with adding data to a
database in
> > code before, how did you handle it?
> >
> > John Warner
> >
> >
> > > -----Original Message-----
> > > From: Johnson, Peter
[mailto:Peter.Johnsonmercer.com]
> > > Sent: Thursday, June 14, 2007 4:56 PM
> > > To: aspnetaspadvice.com
> > > Subject: [aspnet] RE: VB.NET test for DBNull
> > >
> > >
> > > If you don't need user interaction, you might
skip VB.NET
> > altogether
> > > and write SQL Server DTS import
packages/scripts.
> > >
> > > There are nulls in a database context
(DBNull) and nulls
> in a .NET
> > > context (Nothing in VB.NET), which might be
part of the
> > > misunderstanding. If you're selecting nulls
out of the first SQL
> > > Server database, you might try this:
> > >
> > > If FieldOfTypeDate = DBNull.Value Then
> > >
> > > Although, if it's just going back into SQL
Server,
> depending on how
> > > you're doing it (manually building SQL code
inline? bad idea...
> > > parameters?), you may not need to do anything
special for
> > nulls going
> > > right back into the other database.
> > >
> > > --Peter
> > >
> > >
> > > > -----Original Message-----
> > > > From: John Warner [mailto:johnjwarner.com]
> > > > Sent: Thursday, June 14, 2007 4:46 PM
> > > > To: aspnetaspadvice.com
> > > > Subject: [aspnet] VB.NET test for
DBNull
> > > >
> > > >
> > > > How do I test a field coming in (not
user supplied in this
> > > > case) for a NULL
> > > > before inserting it into my SQL Server
database? I have
> > seen on the
> > > > web the examples using string values,
but what of the other data
> > > types such as
> > > > decimal or datetime? In VB.NET (v 1.1)
the IS operator is not
> > > > allowed in the following:
> > > >
> > > > Dim MyNull as System.Data.DBNull
> > > >
> > > > If FieldOfTypeDate Is MyNull <
errors out 'Is' not allowed
> > > > also "=" is not allowed. So
how does one test for null when the
> > > > data type is not a string?
> > > >
> > > > Is there any REAL substitute for the old
IsNull() function from
> > > > classic VB?
> > > >
> > > > What I'm trying to do is move some data
from one database into
> > > > another, both are not SQL Server only
the target
> database is. I
> > > > need to check for
> > > > Null before creating my Insert
statement, but testing results
> > > > in an error
> > > > if the incoming data type is anything
other then a
> > > > string/char. For example
> > > > if the old database has nothing in a
date field, I need to
> > > > insert a NULL
> > > > into SQL Server, but I can't seem to
test for this
> > condition without
> > > > creating an error.
> > > >
> > > > How do those of you more experienced
then me deal with NULL?
> > > >
> > > > Thanks,
> > > >
> > > > John Warner
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