DataServiceContext.AddLink 메서드

DataServiceContext에서 추적 중인 개체 집합에 지정된 링크를 추가합니다.

네임스페이스:  System.Data.Services.Client
어셈블리:  Microsoft.Data.Services.Client(Microsoft.Data.Services.Client.dll)

구문

‘선언
Public Sub AddLink ( _
    source As Object, _
    sourceProperty As String, _
    target As Object _
)
‘사용 방법
Dim instance As DataServiceContext
Dim source As Object
Dim sourceProperty As String
Dim target As Object

instance.AddLink(source, sourceProperty, _
    target)

public void AddLink(
    Object source,
    string sourceProperty,
    Object target
)

public:
void AddLink(
    Object^ source, 
    String^ sourceProperty, 
    Object^ target
)

member AddLink : 
        source:Object * 
        sourceProperty:string * 
        target:Object -> unit 

public function AddLink(
    source : Object, 
    sourceProperty : String, 
    target : Object
)

매개 변수

• source
  유형: System.Object
  새 링크의 원본 개체입니다.

• sourceProperty
  유형: System.String
  관련 개체를 반환하는 원본 개체의 탐색 속성 이름입니다.

• target
  유형: System.Object
  새 링크를 통해 원본 개체와 관련된 개체입니다.

예외

주의

관련 원본 및 대상 개체 간에 새 링크가 있고 이 링크가 지정된 원본 속성으로 표현됨을 DataServiceContext에 알립니다. DataServiceContext는 다음에 SaveChanges를 호출할 때 데이터 서비스로 전송할 새로 만든 링크 집합에 이 링크를 추가합니다. 자세한 내용은 데이터 서비스 업데이트(WCF Data Services)를 참조하십시오.

대상 개체는 sourceProperty 매개 변수 또는 해당 형식의 하위 형식으로 식별되는 형식이어야 합니다.

예

다음 예제에서는 AddLink 및 SetLink 메서드를 사용하여 관계를 정의하는 링크를 만드는 방법을 보여 줍니다. 이 예제에서는 Order_Details 개체에 대한 탐색 속성도 명시적으로 설정됩니다. 이 예제에서는 WCF Data Services?퀵 스타트를 완료하면 생성되는 Northwind 데이터 서비스를 기반으로 서비스 참조 추가 도구에서 생성된 DataServiceContext를 사용합니다.

Dim productId = 25
Dim customerId = "ALFKI"

Dim newItem As Order_Detail = Nothing

' Create the DataServiceContext using the service URI.
Dim context = New NorthwindEntities(svcUri)

Try
    ' Get the specific product.
    Dim selectedProduct = (From product In context.Products _
                                           Where product.ProductID = productId _
                                           Select product).Single()

    ' Get the specific customer.
    Dim cust = (From customer In context.Customers.Expand("Orders") _
                Where customer.CustomerID = customerId _
                Select customer).Single()

    ' Get the first order. 
    Dim order = cust.Orders.FirstOrDefault()

    ' Create a new order detail for the specific product.
    newItem = Order_Detail.CreateOrder_Detail( _
    order.OrderID, selectedProduct.ProductID, 10, 5, 0)

    ' Add the new order detail to the context.
    context.AddToOrder_Details(newItem)

    ' Add links for the one-to-many relationships.
    context.AddLink(order, "Order_Details", newItem)
    context.AddLink(selectedProduct, "Order_Details", newItem)

    ' Add the new order detail to the collection, and
    ' set the reference to the product.
    order.Order_Details.Add(newItem)
    newItem.Product = selectedProduct

    ' Send the insert to the data service.
    Dim response As DataServiceResponse = context.SaveChanges()

    ' Enumerate the returned responses.
    For Each change As ChangeOperationResponse In response
        ' Get the descriptor for the entity.
        Dim descriptor = TryCast(change.Descriptor, EntityDescriptor)

        If Not descriptor Is Nothing Then

            Dim addedProduct = TryCast(descriptor.Entity, Product)

            If Not addedProduct Is Nothing Then
                Console.WriteLine("New product added with ID {0}.", _
                    addedProduct.ProductID)
            End If
        End If
    Next
Catch ex As DataServiceQueryException
    Throw New ApplicationException( _
            "An error occurred when saving changes.", ex)

    ' Handle any errors that may occur during insert, such as 
    ' a constraint violation.
Catch ex As DataServiceRequestException
    Throw New ApplicationException( _
            "An error occurred when saving changes.", ex)

int productId = 25;
string customerId = "ALFKI";

Order_Detail newItem = null;

// Create the DataServiceContext using the service URI.
NorthwindEntities context = new NorthwindEntities(svcUri);

try
{
    // Get the specific product.
    var selectedProduct = (from product in context.Products
                           where product.ProductID == productId
                           select product).Single();

    // Get the specific customer.
    var cust = (from customer in context.Customers.Expand("Orders")
                where customer.CustomerID == customerId
                select customer).Single();

    // Get the first order. 
    Order order = cust.Orders.FirstOrDefault();

    // Create a new order detail for the specific product.
    newItem = Order_Detail.CreateOrder_Detail(
        order.OrderID, selectedProduct.ProductID, 10, 5, 0);

    // Add the new order detail to the context.
    context.AddToOrder_Details(newItem);

    // Add links for the one-to-many relationships.
    context.AddLink(order, "Order_Details", newItem);
    context.AddLink(selectedProduct, "Order_Details", newItem);

    // Add the new order detail to the collection, and
    // set the reference to the product.
    order.Order_Details.Add(newItem);
    newItem.Product = selectedProduct;

    // Send the changes to the data service.
    DataServiceResponse response = context.SaveChanges();

    // Enumerate the returned responses.
    foreach (ChangeOperationResponse change in response)
    {
        // Get the descriptor for the entity.
        EntityDescriptor descriptor = change.Descriptor as EntityDescriptor;

        if (descriptor != null)
        {
            if (descriptor.Entity.GetType() == typeof(Order_Detail))
            {
                Order_Detail addedItem = descriptor.Entity as Order_Detail;

                if (addedItem != null)
                {
                    Console.WriteLine("New {0} item added to order {1}.",
                        addedItem.Product.ProductName, addedItem.OrderID.ToString());
                }
            }
        }
    }
}
catch (DataServiceQueryException ex)
{
    throw new ApplicationException(
        "An error occurred when saving changes.", ex);
}

// Handle any errors that may occur during insert, such as 
// a constraint violation.
catch (DataServiceRequestException ex)
{
    throw new ApplicationException(
        "An error occurred when saving changes.", ex);
}

참고 항목

참조

DataServiceContext 클래스

System.Data.Services.Client 네임스페이스