ObjectStateManager.GetObjectStateEntry Method (EntityKey)

 

Returns an ObjectStateEntry for the object or relationship entry with the specified key.

Namespace:   System.Data.Objects
Assembly:  System.Data.Entity (in System.Data.Entity.dll)

public ObjectStateEntry GetObjectStateEntry(
	EntityKey key
)

Parameters

key
Type: System.Data.EntityKey

The EntityKey.

Return Value

Type: System.Data.Objects.ObjectStateEntry

The corresponding ObjectStateEntry for the given EntityKey.

Exception Condition
ArgumentNullException

When key is null.

ArgumentException

When the specified key cannot be found in the state manager.

InvalidOperationException

No entity with the specified EntityKey exists in the ObjectStateManager.

Use the TryGetObjectStateEntry(EntityKey, ObjectStateEntry) method to return an ObjectStateEntry object without having to handle the InvalidOperationException raised by the GetObjectStateEntry(EntityKey) method.

The example in this topic is based on the AdventureWorks Sales Model. The example gets the ObjectStateEntry for the given EntityKey from the ObjectStateManager. Then it gets the current value of the SalesOrderHeader.PurchaseOrderNumber property, changes the property's value, and enumerates through the collection of modified properties.

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

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    try
    {
        var order = (from o in context.SalesOrderHeaders
                     where o.SalesOrderID == orderId
                     select o).First();

        // Change the status of an existing order.
        order.Status = 1;

        // Delete the first item in the order.
        context.DeleteObject(order.SalesOrderDetails.First());

        // 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 = 0,
            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);

        // Get the ObjectStateEntry for the order.
        ObjectStateEntry stateEntry =
            context.ObjectStateManager
            .GetObjectStateEntry(order);
        Console.WriteLine("State before SaveChanges() is called: {0}",
            stateEntry.State.ToString());

        // Save changes in the object context to the database.
        int changes = context.SaveChanges();

        Console.WriteLine("State after SaveChanges() is called: {0}",
            stateEntry.State.ToString());

        Console.WriteLine(changes.ToString() + " changes saved!");
        Console.WriteLine("Updated item for order ID: "
            + order.SalesOrderID.ToString());

        // Iterate through the collection of SalesOrderDetail items.
        foreach (SalesOrderDetail item in order.SalesOrderDetails)
        {
            Console.WriteLine("Item ID: "
                + item.SalesOrderDetailID.ToString() + "  Product: "
                + item.ProductID.ToString() + "  Quantity: "
                + item.OrderQty.ToString());
        }
    }
    catch (UpdateException ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

.NET Framework
Available since 3.5
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