Use msclr string marshallers

Author: duckdoom5

include/CppSharp.h

@@ -13,7 +13,7 @@
 #include <string>
 #include <ostream>
 #include <vcclr.h>
-#include <msclr/marshal.h>
+#include <msclr/marshal_cppstd.h>
 
 public interface class ICppInstance
 {
@@ -24,6 +24,23 @@ public interface class ICppInstance
   }
 };
 
+namespace msclr {
+    namespace interop {
+
+        template <>
+        inline System::String^ marshal_as(const std::string_view& _from_obj)
+        {
+            return details::InternalAnsiToStringHelper(_from_obj.data(), _from_obj.length());
+        }
+
+        template <>
+        inline System::String^ marshal_as(const std::wstring_view& _from_obj)
+        {
+            return details::InternalUnicodeToStringHelper(_from_obj.data(), _from_obj.length());
+        }
+    }
+}
+
 // CLI extensions namespace
 namespace clix {
 
@@ -202,18 +219,18 @@ namespace clix {
   /// </remarks>
   /// <param name="string">String to be marshalled to the other side</param>
   /// <returns>The marshaled representation of the string</returns>
-  template<Encoding encoding, typename SourceType>
-  typename detail::IfManaged<SourceType>::Select::Either<
-    typename detail::StringTypeSelector<encoding>::Type,
-    System::String ^
-  >::Type marshalString(SourceType string) {
-      constexpr detail::MarshalingDirection direction =
+  template<Encoding encoding, typename SourceType, class ResultType =
+    typename detail::IfManaged<SourceType>::Select::Either<
+        typename detail::StringTypeSelector<encoding>::Type,
+        System::String^>::Type
+    >
+  ResultType marshalString(SourceType string) {
+      return msclr::interop::marshal_as<ResultType>(string);
+      /*constexpr detail::MarshalingDirection direction =
           detail::IfManaged<SourceType>::Result ? detail::CxxFromNet : detail::NetFromCxx;
       using StringMarshaler = detail::StringMarshaler<direction>;
-
       // Pass on the call to our nifty template routines
-      return StringMarshaler::template marshal<encoding, SourceType>(string);
-
+      return StringMarshaler::template marshal<encoding, SourceType>(string);*/
   }
 
 } // namespace clix