EntityKey Class
Provides a durable reference to an object that is an instance of an entity type.
Assembly: System.Data.Entity (in System.Data.Entity.dll)
The EntityKey type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | EntityKey | Initializes a new instance of the EntityKey class. |
![]() | EntityKey(String, IEnumerable(Of KeyValuePair(Of String, Object))) | Initializes a new instance of the EntityKey class with an entity set name and a generic KeyValuePair collection. |
![]() | EntityKey(String, IEnumerable(Of EntityKeyMember)) | Initializes a new instance of the EntityKey class with an entity set name and an IEnumerable(Of T) collection of EntityKeyMember objects. |
![]() | EntityKey(String, String, Object) | Initializes a new instance of the EntityKey class with an entity set name and specific entity key pair. |
| Name | Description | |
|---|---|---|
![]() | EntityContainerName | Gets or sets the name of the entity container. |
![]() | EntityKeyValues | Gets or sets the key values associated with this EntityKey. |
![]() | EntitySetName | Gets or sets the name of the entity set. |
![]() | IsTemporary | Gets a value that indicates whether the EntityKey is temporary. |
| Name | Description | |
|---|---|---|
![]() | Equals(EntityKey) | Returns a value that indicates whether this instance is equal to a specified EntityKey. |
![]() | Equals(Object) | Returns a value that indicates whether this instance is equal to a specified object. (Overrides Object.Equals(Object).) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetEntitySet | Gets the entity set for this entity key from the given metadata workspace. |
![]() | GetHashCode | Serves as a hash function for the current EntityKey object. GetHashCode is suitable for hashing algorithms and data structures such as a hash table. (Overrides Object.GetHashCode.) |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | OnDeserialized | Helper method that is used to deserialize an EntityKey. |
![]() | OnDeserializing | Helper method that is used to deserialize an EntityKey. |
![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
| Name | Description | |
|---|---|---|
![]() ![]() | Equality | Compares two EntityKey objects. |
![]() ![]() | Inequality | Compares two EntityKey objects. |
| Name | Description | |
|---|---|---|
![]() ![]() | EntityNotValidKey | A simple EntityKey identifying an entity that resulted from a failed TREAT operation. |
![]() ![]() | NoEntitySetKey | A singleton EntityKey by which a read-only entity is identified. |
The EntityKey objects are immutable; that is, after they are constructed they cannot be modified.
For more information, see Working with Entity Keys (Entity Framework).
These examples are based on the Adventure Works Sales Model. The examples show you how to create and use an EntityKey.
Using context As New AdventureWorksEntities() Dim entity As Object = Nothing Dim entityKeyValues As IEnumerable(Of KeyValuePair(Of String, Object)) = _ New KeyValuePair(Of String, Object)() {New KeyValuePair(Of String, Object)("SalesOrderID", 43680)} ' Create the key for a specific SalesOrderHeader object. Dim key As New EntityKey("AdventureWorksEntities.SalesOrderHeaders", entityKeyValues) ' Get the object from the context or the persisted store by its key. If context.TryGetObjectByKey(key, entity) Then Console.WriteLine("The requested " & entity.GetType().FullName & " object was found") Else Console.WriteLine("An object with this key could not be found.") End If End Using
Using context As New AdventureWorksEntities() Try ' Create the key that represents the order. Dim orderKey As New EntityKey("AdventureWorksEntities.SalesOrderHeaders", "SalesOrderID", orderId) ' Create the stand-in SalesOrderHeader object ' based on the specified SalesOrderID. Dim order As New SalesOrderHeader() order.EntityKey = orderKey ' Assign the ID to the SalesOrderID property to matche the key. order.SalesOrderID = CInt(orderKey.EntityKeyValues(0).Value) ' Attach the stand-in SalesOrderHeader object. context.SalesOrderHeaders.Attach(order) ' Create a new SalesOrderDetail object. ' You can use the static CreateObjectName method (the Entity Framework ' adds this method to the generated entity types) instead of the new operator: ' SalesOrderDetail.CreateSalesOrderDetail(1, 0, 2, 750, 1, (decimal)2171.2942, 0, 0, ' Guid.NewGuid(), DateTime.Today)); Dim detail = New SalesOrderDetail With { .SalesOrderID = 0, .SalesOrderDetailID = 0, .OrderQty = 2, .ProductID = 750, .SpecialOfferID = 1, .UnitPrice = CDec(2171.2942), .UnitPriceDiscount = 0, .LineTotal = 0, .rowguid = Guid.NewGuid(), .ModifiedDate = DateTime.Now } order.SalesOrderDetails.Add(detail) context.SaveChanges() Catch generatedExceptionName As InvalidOperationException Console.WriteLine("Ensure that the key value matches the value of the object's ID property.") Catch generatedExceptionName As UpdateException Console.WriteLine("An error has occured. Ensure that an object with the '{0}' key value exists.", orderId) End Try End Using
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.





