Compiler Warning (level 3) C4580

[attribute] is deprecated; instead specify System::Attribute or Platform::Metadata as a base class

Remarks

[attribute] is no longer the preferred syntax for creating user-defined attributes. For more information, see User-Defined Attributes. For CLR code, derive attributes from System::Attribute. For Windows Runtime code, derive attributes from Platform::Metadata.

Example

The following example generates C4580 and shows how to fix it.

// C4580.cpp
// compile with: /W3 /c /clr
[attribute]   // C4580
public ref class Attr {
public:
   int m_t;
};

public ref class Attr2 : System::Attribute {
public:
   int m_t;
};