방법: 프록시를 사용하여 POCO 엔터티 만들기(Entity Framework)

이 항목의 예제에서는 프록시를 사용하여 POCO 엔터티를 만드는 방법을 보여 줍니다. 프록시를 사용하여 POCO 엔터티를 만들려면 POCO 클래스가 POCO 프록시를 만들기 위한 요구 사항(Entity Framework)에 설명된 요구 사항을 충족해야 합니다.

이 항목의 예제에서는 방법: POCO 엔터티 정의(Entity Framework)에 정의된 POCO 클래스와 방법: 사용자 지정 개체를 사용할 수 있도록 모델링 및 매핑 파일 사용자 지정(Entity Framework)에 정의된 AdventureWorks 기반 데이터 모델을 사용합니다.

예제

이 예제에서는 CreateObject 메서드를 사용하여 새 LineItem 개체를 만든 다음 새 LineItem을 기존 Order에 추가합니다.

' Specify the order to update. 
Dim orderId As Integer = 43680

Using context As New POCOAdventureWorksEntities()
    Try
        ' Enable lazy loading. 
        context.ContextOptions.LazyLoadingEnabled = True

        Dim order As Order = context.Orders.Where(Function(o) o.SalesOrderID = orderId).First()
        ' Create a new item and add it to the order. 
        ' The Entity Framework is going to generate 
        ' proxy object for the newItem object. 
        Dim newItem As LineItem = context.CreateObject(Of LineItem)()
        newItem.SalesOrderDetailID = 0
        ' Assign the order to the new LineItem. 
        newItem.SalesOrderID = orderId
        newItem.OrderQty = 1
        newItem.ProductID = 750
        newItem.UnitPriceDiscount = 0
        newItem.UnitPrice = 2171.2942D
        newItem.ModifiedDate = DateTime.Today
        newItem.rowguid = Guid.NewGuid()
        newItem.SpecialOfferID = 1


        ' Add the new item to the order. 
        ' The order will be added to the context because 
        ' we are working with POCO proxies. 
        order.LineItems.Add(newItem)

        ' The state of the newItem is Added. 
        Console.WriteLine(context.ObjectStateManager.GetObjectStateEntry(newItem).State.ToString())

        ' Change the status and ship date of an existing order. 
        order.ShipDate = DateTime.Today

        ' The sate of the order item is Modified. 
        Console.WriteLine(context.ObjectStateManager.GetObjectStateEntry(order).State.ToString())

        ' The newItem is set to Unchanged.
        context.SaveChanges()

        ' Change the newly added item. 
        newItem.OrderQty = 2

        ' The changes are tracked as they occur and the state of the object is Modified. 
        Console.WriteLine(context.ObjectStateManager.GetObjectStateEntry(newItem).State.ToString())

        ' Delete the newly created object. 
        context.DeleteObject(newItem)

        ' Save changes in the object context to the database 
        ' after first detecting changes again. 
        context.SaveChanges()
    Catch ex As UpdateException
        Console.WriteLine(ex.ToString())
    Catch ex As InvalidOperationException
        Console.WriteLine(ex.ToString())
    End Try
End Using

// Specify the order to update.
int orderId = 43680;

using (POCOAdventureWorksEntities context =
        new POCOAdventureWorksEntities())
{
    try
    {
        // Enable lazy loading.
        context.ContextOptions.LazyLoadingEnabled = true;

        Order order = context.Orders.
                          Where(o => o.SalesOrderID == orderId).First();
        // Create a new item and add it to the order.
        // The Entity Framework is going to generate 
        // proxy object for the newItem object. 
        LineItem newItem = context.CreateObject<LineItem>();
        newItem.SalesOrderDetailID = 0;
        // Assign the order to the new LineItem. 
        newItem.SalesOrderID = orderId;
        newItem.OrderQty = 1;
        newItem.ProductID = 750;
        newItem.UnitPriceDiscount = 0;
        newItem.UnitPrice = 2171.2942M;
        newItem.ModifiedDate = DateTime.Today;
        newItem.rowguid = Guid.NewGuid();
        newItem.SpecialOfferID = 1;

        // Add the new item to the order.
        // The order will be added to the context because 
        // we are working with POCO proxies.
        order.LineItems.Add(newItem);

        // The state of the newItem is Added.
        Console.WriteLine(context.ObjectStateManager.GetObjectStateEntry(newItem).State);

        // Change the status and ship date of an existing order.
        order.ShipDate = DateTime.Today;

        // The sate of the order item is Modified.
        Console.WriteLine(context.ObjectStateManager.GetObjectStateEntry(order).State);

        // The newItem is set to Unchanged.
        context.SaveChanges();

        // Change the newly added item.
        newItem.OrderQty = 2;

        // The changes are tracked as they occur and the state of the object is Modified.
        Console.WriteLine(context.ObjectStateManager.GetObjectStateEntry(newItem).State);

        // Delete the newly created object.
        context.DeleteObject(newItem);

        // Save changes in the object context to the database 
        // after first detecting changes again.
        context.SaveChanges();
    }
    catch (UpdateException ex)
    {
        Console.WriteLine(ex.ToString());
    }
    catch (InvalidOperationException ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

참고 항목

작업

방법: POCO 엔터티가 프록시인지 식별(Entity Framework)

개념

POCO 엔터티 사용(Entity Framework)
POCO 엔터티에서 변경 내용 추적(Entity Framework)
개체 사용자 지정(Entity Framework)