ObjectStateManager.TryGetObjectStateEntry Method

Definition

Namespace:

System.Data.Objects

Assembly:

System.Data.Entity.dll

Tries to return an ObjectStateEntry object for a specific object or relationship entry.

Overloads

TryGetObjectStateEntry(EntityKey, ObjectStateEntry)	Tries to retrieve the corresponding ObjectStateEntry for the object or relationship with the specified EntityKey.
TryGetObjectStateEntry(Object, ObjectStateEntry)	Tries to retrieve the corresponding ObjectStateEntry for the specified Object.

TryGetObjectStateEntry(EntityKey, ObjectStateEntry)

Tries to retrieve the corresponding ObjectStateEntry for the object or relationship with the specified EntityKey.

public:
 bool TryGetObjectStateEntry(System::Data::EntityKey ^ key, [Runtime::InteropServices::Out] System::Data::Objects::ObjectStateEntry ^ % entry);

public bool TryGetObjectStateEntry (System.Data.EntityKey key, out System.Data.Objects.ObjectStateEntry entry);

member this.TryGetObjectStateEntry : System.Data.EntityKey * ObjectStateEntry -> bool

Public Function TryGetObjectStateEntry (key As EntityKey, ByRef entry As ObjectStateEntry) As Boolean

Parameters

key

EntityKey

The given EntityKey.

entry

ObjectStateEntry

When this method returns, contains an ObjectStateEntry for the given EntityKey This parameter is passed uninitialized.

Returns

Boolean

A Boolean value that is true if there is a corresponding ObjectStateEntry for the given EntityKey; otherwise, false.

Exceptions

ArgumentNullException

A null (Nothing in Visual Basic) value is provided for key.

Examples

The following example attempts to retrieve the corresponding ObjectStateEntry for the given EntityKey.

int orderId = 43680;

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    ObjectStateManager objectStateManager = context.ObjectStateManager;
    ObjectStateEntry stateEntry = null;

    var order = (from o in context.SalesOrderHeaders
                 where o.SalesOrderID == orderId
                 select o).First();

    // Attempts to retrieve ObjectStateEntry for the given EntityKey.
    bool isPresent = objectStateManager.TryGetObjectStateEntry(((IEntityWithKey)order).EntityKey, out stateEntry);
    if (isPresent)
    {
        Console.WriteLine("The entity was found");
    }
}

The following example uses the TryGetObjectStateEntry(EntityKey, ObjectStateEntry) method on the returned ObjectStateManager to get an object based on its entity key.

private static void ApplyItemUpdates(SalesOrderDetail originalItem,
    SalesOrderDetail updatedItem)
{
    using (AdventureWorksEntities context =
        new AdventureWorksEntities())
    {
        context.SalesOrderDetails.Attach(updatedItem);
        // Check if the ID is 0, if it is the item is new.
        // In this case we need to chage the state to Added.
        if (updatedItem.SalesOrderDetailID == 0)
        {
            // Because the ID is generated by the database we do not need to
            // set updatedItem.SalesOrderDetailID.
            context.ObjectStateManager.ChangeObjectState(updatedItem, System.Data.EntityState.Added);
        }
        else
        {
            // If the SalesOrderDetailID is not 0, then the item is not new
            // and needs to be updated. Because we already added the
            // updated object to the context we need to apply the original values.
            // If we attached originalItem to the context
            // we would need to apply the current values:
            // context.ApplyCurrentValues("SalesOrderDetails", updatedItem);
            // Applying current or original values, changes the state
            // of the attached object to Modified.
            context.ApplyOriginalValues("SalesOrderDetails", originalItem);
        }
        context.SaveChanges();
    }
}

Remarks

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

TryGetObjectStateEntry(Object, ObjectStateEntry)

Tries to retrieve the corresponding ObjectStateEntry for the specified Object.

public:
 bool TryGetObjectStateEntry(System::Object ^ entity, [Runtime::InteropServices::Out] System::Data::Objects::ObjectStateEntry ^ % entry);

public bool TryGetObjectStateEntry (object entity, out System.Data.Objects.ObjectStateEntry entry);

member this.TryGetObjectStateEntry : obj * ObjectStateEntry -> bool

Public Function TryGetObjectStateEntry (entity As Object, ByRef entry As ObjectStateEntry) As Boolean

Parameters

entity

Object

The Object to which the retrieved ObjectStateEntry belongs.

entry

ObjectStateEntry

When this method returns, contains the ObjectStateEntry for the given EntityKey This parameter is passed uninitialized.

Returns

Boolean

A Boolean value that is true if there is a corresponding ObjectStateEntry for the given object; otherwise, false.

Remarks

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