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KeyAttribute Class

Specifies one or more entity properties to use as the unique identity for the entity.

System.Object
  System.Attribute
    System.ComponentModel.DataAnnotations.KeyAttribute

Namespace:  System.ComponentModel.DataAnnotations
Assembly:  System.ComponentModel.DataAnnotations (in System.ComponentModel.DataAnnotations.dll)

[AttributeUsageAttribute(AttributeTargets.Property|AttributeTargets.Field, AllowMultiple = false, 
	Inherited = true)]
public sealed class KeyAttribute : Attribute

The KeyAttribute type exposes the following members.

  NameDescription
Public methodKeyAttributeInitializes a new instance of the KeyAttribute class.
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  NameDescription
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.)
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You apply the KeyAttribute attribute to one or more properties to specify the values that uniquely identify the entity object.

The following example shows a KeyAttribute applied to a property named ProductID that uniquely identifies the individual data records represented by this class.


public class Product
{
  [Key]
  public integer ProductID { get; set; }
}


Silverlight

Supported in: 5, 4, 3

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

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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