[RESOLVED] DMax invalid use of null

I am getting an error of Run-time error '94': invalid use of Null. I have the code below. This is when I am creating a new record and there isn't data to add to... I have a default value of 0 in the docSeries column. Any ideas???

Code:

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Option Explicit

Public Function getDocID(TypeID As Integer, series As Single, version As Single) As Long
  Dim strWhere As String
  strWhere = "DocType = " & TypeID & " AND DocSeries = " & series & " AND DocVersion = " & version
  getDocID = Nz(DLookup("DocID", "tblDocInfo", strWhere))
End Function

Public Function getSeries(docID As Long) As Single
  On Error GoTo errlabel
  Const fldName = "DocSeries"
  Const tblName = "tblDocInfo"
  getSeries = DLookup(fldName, tblName, "DocID = " & docID)
  Exit Function
errlabel:
  MsgBox Err.Number & " " & Err.Description
End Function

Public Function getNextSeries(docID As Long) As Single
  getNextSeries = getSeries(docID) + 0.001
End Function

Public Function getMaxSeriesForType(TypeID As Integer) As Single
  Const fldName = "DocSeries"
  Const tblName = "tblDocInfo"
  Const typeName = "DocType"
  Dim strWhere As String
  strWhere = typeName & " = " & TypeID
  getMaxSeriesForType = DMax(fldName, tblName, strWhere)
 End Function

Public Function getNextSeriesForType(TypeID As Integer) As Single
  getNextSeriesForType = getMaxSeriesForType(TypeID) + 0.001
End Function

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as you don't specify which line gives the error, hard to be precise
try adding a nullstring to the field that may contain a null

If no record exists, DLookup() and DMax() will return a Null value.
You cannot assign a Null value to a Long or a Single variable.
Change 0 to whatever default value you want.

Code:

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  getDocID = Nz(DLookup("DocID", "tblDocInfo", strWhere), 0) '-- Long

  getSeries = Nz(DLookup(fldName, tblName, "DocID = " & docID), 0) '-- Single

  getMaxSeriesForType = Nz(DMax(fldName, tblName, strWhere), 0) '-- Single

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anhn: great solution!! worked perfectly. Thank you SO much!