Solved

Getting DLookup to return a Null value in Access - VB6

Posted on 2006-07-18
7
442 Views
Last Modified: 2012-06-22
Hello experts,

This should be pretty easy but I cannot figure it out.  I am new to VB and having problems.

I am trying to make a form in Access that will allow the user to input their employee number into a textbox.  Once they click the button, it will look for thier name in a table and retreive their info or return a Null value if the number is not found.  I have had not problems having it find records that are there, but I cannot figure out how to make it return a Null if there is no record found.

Here is my code:

' NumberInputTxt , FirstNameTxt , and ValidTxt  are all textboxes
' identipass is the table I am looking in

' the problem is I cannot get varX to = Null.  I have also tried if varX="" which did not work


Private Sub numberinputtxt_Click()

Dim CardNumber As String
Dim varX As Variant

CardNumber = NumberInputTxt.Text

varX = DLookup("[First]", "Identipass", "[Number]= " & CardNumber)

FirstNameTxt = varX

If varX = Null Then
ValidTxt = "Null"

Else

ValidTxt = "Found"
End If

End Sub

----------------------------------------------------------

Thanks in advance!
0
Comment
Question by:paries
  • 4
  • 2
7 Comments
 
LVL 34

Expert Comment

by:flavo
ID: 17133256
If varX Is Null Then
ValidTxt = "Null"

Dave
0
 
LVL 65

Accepted Solution

by:
rockiroads earned 500 total points
ID: 17133291
DLOOKUP always returns null if no record foind

Flavo has given u the right syntax. The other way  is    If IsNull(varx) = True then



Alternativly, u can use NZ to return a string instead

varX = NZ(DLookup("[First]", "Identipass", "[Number]= " & CardNumber),"")
if varX = "" then
    msgbox "Not found"


0
 

Author Comment

by:paries
ID: 17133436
If varX Is Null then    gave me a runtime error 424 for some reason.  The other suggestion worked great.  Thanks
0
Three Reasons Why Backup is Strategic

Backup is strategic to your business because your data is strategic to your business. Without backup, your business will fail. This white paper explains why it is vital for you to design and immediately execute a backup strategy to protect 100 percent of your data.

 
LVL 34

Expert Comment

by:flavo
ID: 17133475
what?
0
 
LVL 34

Expert Comment

by:flavo
ID: 17133500
Well I'll be...I doesn't work :-(

Dave
0
 
LVL 65

Expert Comment

by:rockiroads
ID: 17133615
Dave, thinking about it, I think may be it will work for object references only
0
 
LVL 34

Expert Comment

by:flavo
ID: 17134297
Yeap :-(
0

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I see at least one EE question a week that pertains to using temporary tables in MS Access.  But surprisingly, I was unable to find a single article devoted solely to this topic. I don’t intend to describe all of the uses of temporary tables in t…
As tax season makes its return, so does the increase in cyber crime and tax refund phishing that comes with it
Basics of query design. Shows you how to construct a simple query by adding tables, perform joins, defining output columns, perform sorting, and apply criteria.
Polish reports in Access so they look terrific. Take yourself to another level. Equations, Back Color, Alternate Back Color. Write easy VBA Code. Tighten space to use less pages. Launch report from a menu, considering criteria only when it is filled…

808 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question