Binaryworld - Hex - Convert from decimal to hexadecimal ... [ VB.net -> Math ]

' convert from decimal to hexadecimal
' if you pass the Digits argument, the result is truncated to that number of
' digits
'
' you should always specify Digits if passing negative values

Function Hex(ByVal value As Long, Optional ByVal digits As Short = -1) As String
  ' convert to base-16
  Dim res As String = Convert.ToString(value, 16).ToUpper()

  ' truncate or extend the number
  If digits > 0 Then
    If digits < res.Length Then
      ' truncate the result
      res = res.Substring(res.Length - digits)
    ElseIf digits > res.Length Then
      ' we must extend the result to the left
      If value >= 0 Then
        ' extend with zeroes if positive
        res = res.PadLeft(digits, "0"c)
      Else
        ' extend with "F"s if negative
        res = res.PadLeft(digits, "F"c)
      End If
    End If
  End If
  ' return to caller
  Return res
End Function