c++ runtime componet error "Public members signature contains a type of native"

Question

Such as struct A  is a array member of struct B

typedeof value struct A_{

     unsigned long type;  //error 1

}A

value struct B{

   A  a[2];  //error 2

}

The error is "Public members signature contains a type of native" . the two structure is interface to called in c#！

Why?

Thanks!