GenericParameterAttributes Enumeration

Describes the constraints on a generic type parameter of a generic type or method.

This enumeration has a FlagsAttribute attribute that allows a bitwise combination of its member values.

Namespace:  System.Reflection
Assembly:  mscorlib (in mscorlib.dll)

No code example is currently available or this language may not be supported.

Member nameDescription
Supported by Silverlight for Windows PhoneSupported by Xbox 360NoneThere are no special flags.
Supported by Silverlight for Windows PhoneSupported by Xbox 360VarianceMaskSelects the combination of all variance flags. This value is the result of using logical OR to combine the following flags: Contravariant and Covariant.
Supported by Silverlight for Windows PhoneSupported by Xbox 360CovariantThe generic type parameter is covariant. A covariant type parameter can appear as the result type of a method, the type of a read-only field, a declared base type, or an implemented interface.
Supported by Silverlight for Windows PhoneSupported by Xbox 360ContravariantThe generic type parameter is contravariant. A contravariant type parameter can appear as a parameter type in method signatures.
Supported by Silverlight for Windows PhoneSupported by Xbox 360SpecialConstraintMaskSelects the combination of all special constraint flags. This value is the result of using logical OR to combine the following flags: DefaultConstructorConstraint, ReferenceTypeConstraint, and NotNullableValueTypeConstraint.
Supported by Silverlight for Windows PhoneSupported by Xbox 360ReferenceTypeConstraintA type can be substituted for the generic type parameter only if it is a reference type.
Supported by Silverlight for Windows PhoneSupported by Xbox 360NotNullableValueTypeConstraintA type can be substituted for the generic type parameter only if it is a value type and is not nullable.
Supported by Silverlight for Windows PhoneSupported by Xbox 360DefaultConstructorConstraintA type can be substituted for the generic type parameter only if it has a parameterless constructor.

The members of the GenericParameterAttributes enumeration are divided into two groups, the variance group and the special constraints group. To test a GenericParameterAttributes value for variance flags, first perform a bitwise AND operation with VarianceMask. If the result is None, there are no variance flags. Similarly, use SpecialConstraintMask to test for constraint flags.

The following code example defines a generic type Test with two type parameters. The second type parameter has a base class constraint and a reference type constraint. When the program executes, the constraints are examined using the Type::GenericParameterAttributes property and the Type::GetGenericParameterConstraints method.

No code example is currently available or this language may not be supported.

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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