InheritanceMappingAttribute Class

InheritanceMappingAttribute Class

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Maps an inheritance hierarchy in a LINQ to SQL application.


Namespace:  System.Data.Linq.Mapping
Assembly:  System.Data.Linq (in System.Data.Linq.dll)

[AttributeUsageAttribute(AttributeTargets.Class, AllowMultiple = true, Inherited = false)]
public sealed class InheritanceMappingAttribute : Attribute

The InheritanceMappingAttribute type exposes the following members.

Public methodInheritanceMappingAttributeInitializes a new instance of the InheritanceMappingAttribute class.

Public propertyCodeGets or sets the discriminator code value in a mapped inheritance hierarchy.
Public propertyIsDefaultGets or sets whether an object of this type in instantiated when the discriminator value does not match a specified value.
Public propertyTypeGets or sets the type of the class in the hierarchy.

Public methodEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

One InheritanceMappingAttribute is specified per mapped class.

Note the following when you map inheritance hierarchies:

  • All classes in a hierarchy must be mapped to a single table.

  • The table for an inheritance hierarchy must be declared on the mapped type that is at the top of the hierarchy. You cannot specify the table or mapping attributes in a class that is derived from the top class.

  • You can use an interface in a hierarchy, but LINQ does not map it.

  • You can skip a class in the hierarchy when you map classes, but you can query against mapped classes only.

For correct materialization, discriminator code values must be unique and match the values in the database. A row with a discriminator code value that does not exactly match (even by casing) instantiates the class by using IsDefault set to true.

Windows Phone OS

Supported in: 8.1, 8.0

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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