Convert.ToUInt64 (UInt32) converts 32-bit unsigned integer to 64-bit unsigned integer.
Class Sample
Public Shared Sub Main()
Dim numbers() As UInteger = { UInt32.MinValue, 121, 340, UInt32.MaxValue }
Dim result As ULong
For Each number As UInteger In numbers
result = Convert.ToUInt64(number)
Console.WriteLine(result)
Next
End Sub
End Class