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EntityKey 建構函式

定義

初始化 EntityKey 類別的新執行個體。

多載

EntityKey()

初始化 EntityKey 類別的新執行個體。

EntityKey(String, IEnumerable<KeyValuePair<String,Object>>)

使用實體集名稱和泛型 EntityKey 集合,初始化 KeyValuePair 類別的新執行個體。

EntityKey(String, IEnumerable<EntityKeyMember>)

使用實體集名稱和 EntityKey 物件的 IEnumerable<T> 集合,初始化 EntityKeyMember 類別的新執行個體。

EntityKey(String, String, Object)

使用實體集名稱和特定實體索引鍵組,初始化 EntityKey 類別的新執行個體。

EntityKey()

初始化 EntityKey 類別的新執行個體。

public:
 EntityKey();
public EntityKey ();
Public Sub New ()

適用於

EntityKey(String, IEnumerable<KeyValuePair<String,Object>>)

使用實體集名稱和泛型 EntityKey 集合,初始化 KeyValuePair 類別的新執行個體。

public:
 EntityKey(System::String ^ qualifiedEntitySetName, System::Collections::Generic::IEnumerable<System::Collections::Generic::KeyValuePair<System::String ^, System::Object ^>> ^ entityKeyValues);
public EntityKey (string qualifiedEntitySetName, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string,object>> entityKeyValues);
new System.Data.EntityKey : string * seq<System.Collections.Generic.KeyValuePair<string, obj>> -> System.Data.EntityKey
Public Sub New (qualifiedEntitySetName As String, entityKeyValues As IEnumerable(Of KeyValuePair(Of String, Object)))

參數

qualifiedEntitySetName
String

String,它是由實體容器名稱限定的實體集名稱。

entityKeyValues
IEnumerable<KeyValuePair<String,Object>>

泛型 KeyValuePair 集合。

每個索引鍵/值組都具有屬性名稱 (當做索引鍵) 和該屬性的值 (當做值)。 屬於 EntityKey 一部分的每個屬性都應該具有一組。 雖然索引鍵/值組的順序不重要,但是每個索引鍵屬性都應該包含在內。 這些屬性名稱是未以實體類型名稱或結構描述名稱限定的簡單名稱。

範例

此範例示範如何建立和使用 EntityKey

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    try
    {
        // Create the key that represents the order.
        EntityKey orderKey =
            new EntityKey("AdventureWorksEntities.SalesOrderHeaders",
                "SalesOrderID", orderId);

        // Create the stand-in SalesOrderHeader object
        // based on the specified SalesOrderID.
        SalesOrderHeader order = new SalesOrderHeader();
        order.EntityKey = orderKey;

        // Assign the ID to the SalesOrderID property to matche the key.
        order.SalesOrderID = (int)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));
        SalesOrderDetail detail = new SalesOrderDetail
        {
            SalesOrderID = orderId,
            SalesOrderDetailID = 0,
            OrderQty = 2,
            ProductID = 750,
            SpecialOfferID = 1,
            UnitPrice = (decimal)2171.2942,
            UnitPriceDiscount = 0,
            LineTotal = 0,
            rowguid = Guid.NewGuid(),
            ModifiedDate = DateTime.Now
        };

        order.SalesOrderDetails.Add(detail);

        context.SaveChanges();
    }
    catch (InvalidOperationException)
    {
        Console.WriteLine("Ensure that the key value matches the value of the object's ID property.");
    }
    catch (UpdateException)
    {
        Console.WriteLine("An error has occurred. Ensure that an object with the '{0}' key value exists.",
        orderId);
    }
}

適用於

EntityKey(String, IEnumerable<EntityKeyMember>)

使用實體集名稱和 EntityKey 物件的 IEnumerable<T> 集合,初始化 EntityKeyMember 類別的新執行個體。

public:
 EntityKey(System::String ^ qualifiedEntitySetName, System::Collections::Generic::IEnumerable<System::Data::EntityKeyMember ^> ^ entityKeyValues);
public EntityKey (string qualifiedEntitySetName, System.Collections.Generic.IEnumerable<System.Data.EntityKeyMember> entityKeyValues);
new System.Data.EntityKey : string * seq<System.Data.EntityKeyMember> -> System.Data.EntityKey
Public Sub New (qualifiedEntitySetName As String, entityKeyValues As IEnumerable(Of EntityKeyMember))

參數

qualifiedEntitySetName
String

String,它是由實體容器名稱限定的實體集名稱。

entityKeyValues
IEnumerable<EntityKeyMember>

要用來初始化索引鍵之 IEnumerable<T> 物件的 EntityKeyMember 集合。

適用於

EntityKey(String, String, Object)

使用實體集名稱和特定實體索引鍵組,初始化 EntityKey 類別的新執行個體。

public:
 EntityKey(System::String ^ qualifiedEntitySetName, System::String ^ keyName, System::Object ^ keyValue);
public EntityKey (string qualifiedEntitySetName, string keyName, object keyValue);
new System.Data.EntityKey : string * string * obj -> System.Data.EntityKey
Public Sub New (qualifiedEntitySetName As String, keyName As String, keyValue As Object)

參數

qualifiedEntitySetName
String

String,它是由實體容器名稱限定的實體集名稱。

keyName
String

String,它是索引鍵的名稱。

keyValue
Object

Object,它是索引鍵值。

範例

此範例示範如何建立和使用 EntityKey

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    try
    {
        // Create the key that represents the order.
        EntityKey orderKey =
            new EntityKey("AdventureWorksEntities.SalesOrderHeaders",
                "SalesOrderID", orderId);

        // Create the stand-in SalesOrderHeader object
        // based on the specified SalesOrderID.
        SalesOrderHeader order = new SalesOrderHeader();
        order.EntityKey = orderKey;

        // Assign the ID to the SalesOrderID property to matche the key.
        order.SalesOrderID = (int)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));
        SalesOrderDetail detail = new SalesOrderDetail
        {
            SalesOrderID = orderId,
            SalesOrderDetailID = 0,
            OrderQty = 2,
            ProductID = 750,
            SpecialOfferID = 1,
            UnitPrice = (decimal)2171.2942,
            UnitPriceDiscount = 0,
            LineTotal = 0,
            rowguid = Guid.NewGuid(),
            ModifiedDate = DateTime.Now
        };

        order.SalesOrderDetails.Add(detail);

        context.SaveChanges();
    }
    catch (InvalidOperationException)
    {
        Console.WriteLine("Ensure that the key value matches the value of the object's ID property.");
    }
    catch (UpdateException)
    {
        Console.WriteLine("An error has occurred. Ensure that an object with the '{0}' key value exists.",
        orderId);
    }
}

適用於