Convert.ToUInt32 (UInt64) converts 64-bit unsigned integer to 32-bit unsigned integer.
Class Sample Public Shared Sub Main() Dim numbers() As ULong = { UInt64.MinValue, 121, 340, UInt64.MaxValue } Dim result As UInteger For Each number As ULong In numbers Try result = Convert.ToUInt32(number) Console.WriteLine(result) Catch e As OverflowException Console.WriteLine("The {0} value {1} is outside the range of the UInt32 type.", _ number.GetType().Name, number) End Try Next End Sub End Class