diff --git a/vnpy/api/oes/vnoes/include/autocxxpy/casters.hpp b/vnpy/api/oes/vnoes/include/autocxxpy/casters.hpp
index da3b5329..8ab6d79f 100644
--- a/vnpy/api/oes/vnoes/include/autocxxpy/casters.hpp
+++ b/vnpy/api/oes/vnoes/include/autocxxpy/casters.hpp
@@ -55,13 +55,14 @@ namespace autocxxpy
         template <class to_type, class scope_type>
         static auto try_generate(scope_type &m, const char *name)
         {
-            if constexpr (is_defined_v<to_type>) {
-                if constexpr (!std::is_array_v<to_type>) {
-                    if constexpr (std::is_default_constructible_v<to_type>) {
-                        generate_nocheck<to_type>(m, name);
+            if constexpr (std::is_class_v<to_type> || std::is_enum_v<to_type>) {
+                if constexpr (is_defined_v<to_type>) {
+                    if constexpr (!std::is_array_v<to_type>) {
+                        if constexpr (std::is_default_constructible_v<to_type>) {
+                            generate_nocheck<to_type>(m, name);
+                        }
                     }
                 }
-
             }
         }
     private: