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ObjectStateManager.TryGetObjectStateEntry Method (EntityKey, ObjectStateEntry)

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

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

public bool TryGetObjectStateEntry(
	EntityKey key,
	out ObjectStateEntry entry
)

Parameters

key
Type: System.Data.EntityKey

The given EntityKey.

entry
Type: System.Data.Objects.ObjectStateEntry

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

Return Value

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

ExceptionCondition
ArgumentNullException

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

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

The examples in this topic are based on the Adventure Works Sales Model.

The 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();
    }
}

.NET Framework

Supported in: 4.5, 4, 3.5 SP1

.NET Framework Client Profile

Supported in: 4

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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