reader with blank or null records - vb.net

Question

Thought the code would catch empty records but it turns out it has not been and no error.
turns out my function always returns FALSE
Try
conn.Open()
Dim strQuery As String = "Select * FROM [UsersDataTbl] " & _
"WHERE [UserName] = """ & UserName & """"
Dim comm As New Data.OleDb.OleDbCommand(strQuery, conn)
Dim reader As Data.OleDb.OleDbDataReader = comm.ExecuteReader()
While reader.Read()
If noNull(reader("StudentID") = "") _
Or noNull(reader("LastName") = "") _
Or noNull(reader("FirstName") = "") _
Or noNull(reader("Affiliation") = "") Then
BlankFields = True
Else
BlankFields = False
End If
End While
conn.Close()
Catch ex As Exception
ADDED:
found my noNull method:
Public Function noNull(ByRef o As Object) As String
If (o Is Nothing) Then
Return ""
End If
Return o.ToString()
End Function

Answer 1

I process recordfield values like this:
Dim iVal As Integer = NoNull(r.Fields("someintegerfield").Value, "0", False)
Public Function NoNull(ByVal uAny As Object, Optional ByVal uFillString As String = "", Optional ByVal uTreatDecimalNullAsNothing As Boolean = False) As String
Dim sRet As String = String.Empty
If Not Convert.IsDBNull(uAny) AndAlso Not uAny Is Nothing Then
Debug.Assert(uAny.GetType.ToString <> "cField") 'checking if the argument is a "cField" helps me to check whether I passes "r.fields("somefield").value to this function, or if I forgot the ".value")
sRet = uAny
Else
sRet = String.Empty
End If
If StrLen(sRet) = 0 Then
If modStrings.StrLen(uFillString) > 0 Then
sRet = uFillString
End If
End If
If uTreatDecimalNullAsNothing Then
If sRet = "0" Then
sRet = uFillString
End If
End If
Return sRet
End Function
Public Function StrLen(ByVal uString As String) As Integer
If (Not uString Is Nothing) AndAlso (Not uString = "") Then
Return uString.Length
Else
Return 0
End If
End Function

Answer 2

I hope this can help you.
Dim con As New System.Data.OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=H:\yourDB.accdb;")
Dim cb As String = "SELECT * FROM Table1 "
Dim dr As System.Data.OleDb.OleDbDataReader
Dim cmd As New System.Data.OleDb.OleDbCommand
cmd.Connection = con
cmd.CommandText = cb
con.Open()
dr = cmd.ExecuteReader
While dr.Read()
If Not IsDBNull(dr("value1")) Then MessageBox.Show(dr("value1"))
End While
con.Close()

Answer 3

Supposing that the noNull method is something like this
Public Function noNull(dbValue As Object) as Boolean
if dbValue = DBNull.Value OrElse dbValue = "" Then
return True
else
return False
End If
End Function
Then you call it with
....
noNull(reader("LastName") = "")
....
This means that you compare the value of the LastName field to an Empty string and the result is a boolean True or False, but passing a Boolean value to noNull means that it will never be equal to an empty string or to a DBNull.Value and thus it will return always false
You need to call the method with
If noNull(reader("StudentID")) _
Or noNull(reader("LastName")) _
Or noNull(reader("FirstName")) _
Or noNull(reader("Affiliation")) Then
Or without the noNull method
If reader.IsDBNull(reader.GetOrdinal("StudentID")) _
OrElse reader("StudentID") = "" _
OrElse reader.IsDBNull(reader.GetOrdinal("LastName")) _
OrElse reader("LastName") = ""
OrElse reader.IsDBNull(reader.GetOrdinal("FirstName")) _
OrElse reader("FirstName") = "" _
OrElse reader.IsDBNull(reader.GetOrdinal("Affiliation")) _
OrElse reader("Affiliation") = "" Then
BlankFields = True
Else
BlankFields = False
End If
As you can see this is really ugly, so I suppose that a method like noNull iomplemented above could be useful in this context
EDIT Now, looking at the code of your noNull method then it is clear where is the error.
You should just change the parenthesis position.
If noNull(reader("StudentID")) = "" _
Or noNull(reader("LastName")) = "" _
Or noNull(reader("FirstName")) = "" _
Or noNull(reader("Affiliation")) = "" Then