"Invalid use of Null" issue

[Mark]

Hi all,

How can I keep from getting the "Invalid use of Null" error if the
dateofReferral is indeed null?

vRefDate = DLookup("[dateofreferral]", "tbdetail", "RecordID =
Forms![frmain]!cbPatientList")

 

[John W. Vinson]

Hi all,

How can I keep from getting the "Invalid use of Null" error if the
dateofReferral is indeed null?

vRefDate = DLookup("[dateofreferral]", "tbdetail", "RecordID =
Forms![frmain]!cbPatientList")

Dim vRefDate as a Variant. How is it dimensioned at present?

Or you could use the NZ() function to return some arbitrary date.

 

[MikeJohnB]

Try

vRefDate = NZ(DLookup("[dateofreferral]", "tbdetail", "RecordID =
Forms![frmain]!cbPatientList"),"")

(Will return "" if Null without error I think)

 

[richaluft]

Hi all,

How can I keep from getting the "Invalid use of Null" error if the
dateofReferral is indeed null?

vRefDate = DLookup("[dateofreferral]", "tbdetail", "RecordID =
Forms![frmain]!cbPatientList")

Marc;
You can code using an Iff function as in
vRefdate=Iff(isnull(DLookup-------------)truevalue, false value)

 

[Allen Browne]

John Vinson's answer will solve the problem for you.

For an explanation, see:
Common errors with Null
at:
http://allenbrowne.com/casu-12.html
It's error number 4.