Convert.ToUInt64 (Int64) converts 64-bit signed integer to 64-bit unsigned integer.
Class Sample Public Shared Sub Main() Dim numbers() As Long = { Int64.MinValue, -19432, -18, 0, 121, 340, Int64.MaxValue } Dim result As ULong For Each number As Long In numbers Try result = Convert.ToUInt64(number) Console.WriteLine(result) Catch e As OverflowException Console.WriteLine("The {0} value {1} is outside the range of the UInt64 type.", _ number.GetType().Name, number) End Try Next End Sub End Class