is there any alternative for Any keywork in .net

Hi,
I have migrated ActiveX (VB6) project in .net (.exe type project)    Is it right ?
after migration I am getting some errors

1- For VarPtr (vb6 function) any alternate function in .net

2- In my application used  CopyMemory Lib "kernel32" with paratmeter any.
   I tried by replacign any with object not working.

3- One structure is there and passing object of structure to CopyMemory function
    
    Public Structure udtGUID
        Dim Data1 As Integer
        Dim Data2 As Short
        Dim Data3 As Short
        Dim Data4() As Byte       
        Public Sub Initialize()
            ReDim Data4(7)
        End Sub
    End Structure

   
 Dim rClsId As udtGUID
 CopyMemory(rClsId, riid, Len(rClsId))

Is there any alternative for CopyMemory in .net

Thanks