Unlike previous Visual Basic versions, under VB.NET you can’t use the Len function to calculate the length of a Structure or a class. However, it is easy to get this information with the SizeOf static method of the System.Runtime.InteropServices.Mashal class, as in:

Imports System.Runtime.InteropServicesModule Module1    ' Notice that this structure contains 2 padding bytes between    ' the first two elements    Structure MyStruct        Public el1 As Short        Public el2 As Integer        Public el3 As String    End Structure    Sub Main(ByVal args() As String)        Dim struct As mystruct        Console.WriteLine(Marshal.SizeOf(struct))   ' => 12    End SubEnd Module