compiler-error-c3227.md

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Learn more about: Compiler Error C3227	Compiler Error C3227	11/04/2016	C3227	C3227	7939c23a-96c8-43c2-89e9-f217d132d155

Compiler Error C3227

'parameter' : cannot use 'keyword' to allocate a generic type

In order to instantiate a type, an appropriate constructor is required. However, the compiler is not able to ensure that an appropriate constructor is available.

You can use templates instead of generics to resolve this error, or you can use one of several methods to create an instance of the type.

Example

The following sample generates C3227.

// C3227.cpp
// compile with: /clr /c
generic<class T> interface class ICreate {
   static T Create();
};

generic <class T>
where T : ICreate<T>
ref class C {
   void f() {
      T t = new T;   // C3227

      // OK
      T t2 = ICreate<T>::Create();
      T t3 = safe_cast<T>( System::Activator::CreateInstance(T::typeid) );
   }
};