The types of positional and named parameters for an attribute class are limited to the attribute parameter types, which are:

• One of the following types: bool , byte , char , double , float , int , long , short , string.
• The type object.
• The type System.Type.
• An enum type, provided it has public accessibility and the types in which it is nested (if any) also have public accessibility.
• Single-dimensional arrays of the above types.