How to get rid of warning.

[enliven60411]

This the waring I get:
Warning 4 Function 'UnmaskSSN' doesn't return a value on all code paths. A null reference exception could occur at run time when the result is used.

Private Function UnmaskSSN(ByVal SSN As String) As String

        ' Yank dashes out of the SSN in the masked textbox
        If SSN = "   -  -    " Then
            SSN = "d"
        Else
            If Len(SSN) = 11 Then
                Dim UnmaskedSSN As String = Microsoft.VisualBasic.Left(SSN, 3) & Microsoft.VisualBasic.Mid(SSN, 5, 2) & Microsoft.VisualBasic.Right(SSN, 4)
                Return UnmaskedSSN
            Else
                SSN = "d"
                MessageBox.Show("The SSN entered is not complete." & vbCrLf & "Please try again.", _
                 "CT Guide Request Search", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
                Me.txtSSN.Focus()
            End If

        End If

    End Function

[Oralloy]

Well, the error code means exactly what it says.

If you follow your code through each of the major code paths, you'll find that when the SSN is empty (your magic string), there is no return value; and when the length of SSN is not 11, there is no return value. Instead, in these paths you set the SSN variable to "d", instead.

You might try something like this, instead:

Private Function UnmaskSSN(ByVal SSN As String) As String 
  Dim result as string
  result = "d"

  If Len(SSN) <> 11 Then 
    MessageBox.Show("The SSN entered is not complete." & _
                    vbCrLf & "Please try again.", _ 
                    "CT Guide Request Search", _
                    MessageBoxButtons.OK, _
                    MessageBoxIcon.Exclamation) 
    Me.txtSSN.Focus()
  Else If SSN = "   -  -    " Then 
    '' noOp - result already has "bad" value
  Else
    '' Yank dashes out of the SSN in the masked textbox 
    result = Microsoft.VisualBasic.Left(SSN, 3) & _
             Microsoft.VisualBasic.Mid(SSN, 5, 2) & _
             Microsoft.VisualBasic.Right(SSN, 4) 
  End If

  UnmaskSSN = result
End Function