asked on

How is this handling a null....and how can I fix it?

I am borrowing this function that was created in VBscript/ASP

Private Function MkPhoneNum(byVal number)
      Dim tmp
      number = CStr( number )
      number = Trim( number )
      number = Replace( number, " ", "" )
      number = Replace( number, "-", "" )
      number = Replace( number, "(", "" )
      number = Replace( number, ")", "" )
      Select Case Len( number )
            Case 7
                  tmp = tmp & Mid( number, 1, 3 ) & "-"
                  tmp = tmp & Mid( number, 4, 4 )
            Case 10
                  tmp = tmp & "(" & Mid( number, 1, 3 ) & ") "
                  tmp = tmp & Mid( number, 4, 3 ) & "-"
                  tmp = tmp & Mid( number, 7, 4 )
            Case 11
                  tmp = tmp & Mid( number, 1, 1 ) & " "
                  tmp = tmp & "(" & Mid( number, 2, 3 ) & ") "
                  tmp = tmp & Mid( number, 5, 3 ) & "-"
                  tmp = tmp & Mid( number, 8, 4 )
            Case Else
                  MkPhoneNum = Null
                  Exit Function
      End Select
      MkPhoneNum = tmp
End Function

However, when I pass a null field through it, it results in the following error:


Microsoft VBScript runtime error '800a005e'

Invalid use of Null: 'CStr'

on line 6...which is the line where it defines
number = CStr( number )

any suggestions for how to fix this to just leave null cases blank????

Thanks!

nauman_ahmed

Use IsDbNull to find if the value that is passed is null:

Example:
Dim MyVar As Object
Dim MyCheck As Boolean
MyCheck = IsDBNull(MyVar) ' Returns False.
MyVar = ""
MyCheck = IsDBNull(MyVar) ' Returns False.
MyVar = System.DBNull.Value
MyCheck = IsDBNull(MyVar) ' Returns True.
MsgBox(MyCheck)

---------------------------------------------------------
Private Function MkPhoneNum(byVal number)
if IsDbNull(number) then
throw ArgumentNullException("number","The parameter number cannot be null")
else

Dim tmp
number = CStr( number )
number = Trim( number )
number = Replace( number, " ", "" )
number = Replace( number, "-", "" )
number = Replace( number, "(", "" )
number = Replace( number, ")", "" )
Select Case Len( number )
Case 7
tmp = tmp & Mid( number, 1, 3 ) & "-"
tmp = tmp & Mid( number, 4, 4 )
Case 10
tmp = tmp & "(" & Mid( number, 1, 3 ) & ") "
tmp = tmp & Mid( number, 4, 3 ) & "-"
tmp = tmp & Mid( number, 7, 4 )
Case 11
tmp = tmp & Mid( number, 1, 1 ) & " "
tmp = tmp & "(" & Mid( number, 2, 3 ) & ") "
tmp = tmp & Mid( number, 5, 3 ) & "-"
tmp = tmp & Mid( number, 8, 4 )
Case Else
MkPhoneNum = Null
Exit Function
End Select
MkPhoneNum = tmp
end if
End Function

HTH, nauman

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tdkh

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htillberg

ASKER

Nice suggestions. The new code by nauman still kept returning the same error though. However, modifying the number line did the trick. Thanks so much!@!!!