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Getting DLookup to return a Null value in Access - VB6

Posted on 2006-07-18
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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
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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
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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

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