Convert.ToUInt64 (Decimal) converts decimal number to 64-bit unsigned integer.
Class Sample Public Shared Sub Main() Dim values() As Decimal = { Decimal.MinValue, -1.23d, -12d, 0d, 147d, _ 199.55d, 2010.16d, Decimal.MaxValue } Dim result As ULong For Each value As Decimal In values Try result = Convert.ToUInt64(value) Console.WriteLine(result) Catch e As OverflowException Console.WriteLine("The {0} value {1} is outside the range of the UInt64 type.", _ value.GetType().Name, value) End Try Next End Sub End Class