Imports System
Imports System.Runtime.InteropServices
 
Public Class Form1
 
    <StructLayout(LayoutKind.Sequential, Pack:=1)> _
    Private Structure MyStruct
        Public id As Integer
        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=20)> _
        Public text As String
    End Structure
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
 
        'Llenamos la estructura con algunos datos
        Dim msg As MyStruct
        msg.id = 888
        msg.text = "Holaaaaaa1"
 
        'La convertimos a Bytes
        Dim bytes As Byte() = StructToByteArray(msg)
 
        'Convertimos el array de bytes a la estructura nuevamente
        Dim msg2 As MyStruct = ByteArrayToStruct(bytes)
        MsgBox(msg2.id)
        MsgBox(msg2.text)
 
    End Sub
 
    Private Function ByteArrayToStruct(ByVal bytes As Byte()) As MyStruct
        Dim handle As GCHandle = GCHandle.Alloc(bytes, GCHandleType.Pinned)
        Dim stuff As MyStruct = DirectCast(Marshal.PtrToStructure(handle.AddrOfPinnedObject(), GetType(MyStruct)), MyStruct)
        handle.Free()
        Return stuff
    End Function
 
    Private Function StructToByteArray(ByVal logFont As MyStruct) As Byte()
        Dim length As Integer = Marshal.SizeOf(logFont)
        Dim ptPoint As IntPtr = Marshal.AllocHGlobal(length)
        Marshal.StructureToPtr(logFont, ptPoint, True)
        Dim bff As Byte() = New Byte(length - 1) {}
        Marshal.Copy(ptPoint, bff, 0, length)
        Marshal.FreeHGlobal(ptPoint)
        Return bff
    End Function
End Class