c# - How do I get marshal size of a specific property from a type in .NET Core? -

in .net core there generic method marshal.sizeof<t>() available (marshal.sizeof(type t) deprecated). enumerate properties of class , marshal size of them. how do?

this code: (not mine code i'm trying port .net core)

from https://github.com/kapetan/dns/blob/master/dns/protocol/marshalling/struct.cs modifications

private static byte[] convertendian<t>(byte[] data) {     var fields = typeof(t).getruntimefields().where(f => f.isstatic == false);     endianattribute endian = typeof(t).gettypeinfo().getcustomattribute<endianattribute>();      foreach (fieldinfo field in fields)     {         if (endian == null && field.getcustomattribute<endianattribute>(false) == null)         {             continue;         }          int offset = marshal.offsetof<t>(field.name).toint32();          // *** deprecated ***         // int length = marshal.sizeof(field.fieldtype);          // *** doesn't work @ ***         int length = field.fieldtype.gettypeinfo().structlayoutattribute.size;          endian = endian ?? field.getcustomattribute<endianattribute>(false);          if (endian.endianness == endianness.big && bitconverter.islittleendian ||                 endian.endianness == endianness.little && !bitconverter.islittleendian)         {             array.reverse(data, offset, length);         }     }      return data; } 

what need decide generic type should used in runtime. there way it: dynamic type.
c# reference says,

the dynamic type enables operations in occurs bypass compile-time type checking. instead, these operations resolved @ run time.

so can define method:

static int getlength<t>(t obj) {     return marshal.sizeof<t>(); } 

and create instance of type t dynamic reflection:

dynamic obj = activator.createinstance(field.fieldtype.gettypeinfo()); int length = getlength(obj); 

the runtime choose suitable type parameter t method.

this solution has limitation can't create instance of type hasn't default constructor. may define wrapper class wrapper<t> no real field, , create runtime in order ensure constructor works. have no idea whether works.