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