ObjectStateManager.TryGetObjectStateEntry ObjectStateManager.TryGetObjectStateEntry ObjectStateManager.TryGetObjectStateEntry ObjectStateManager.TryGetObjectStateEntry Method

Definition

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

Overloads

TryGetObjectStateEntry(EntityKey, ObjectStateEntry) TryGetObjectStateEntry(EntityKey, ObjectStateEntry) TryGetObjectStateEntry(EntityKey, ObjectStateEntry) TryGetObjectStateEntry(EntityKey, ObjectStateEntry)

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

TryGetObjectStateEntry(Object, ObjectStateEntry) TryGetObjectStateEntry(Object, ObjectStateEntry) TryGetObjectStateEntry(Object, ObjectStateEntry) TryGetObjectStateEntry(Object, ObjectStateEntry)

Tries to retrieve the corresponding ObjectStateEntry for the specified Object.

TryGetObjectStateEntry(EntityKey, ObjectStateEntry) TryGetObjectStateEntry(EntityKey, ObjectStateEntry) TryGetObjectStateEntry(EntityKey, ObjectStateEntry) 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 *  -> bool
Public Function TryGetObjectStateEntry (key As EntityKey, ByRef entry As ObjectStateEntry) As Boolean

Parameters

entry
ObjectStateEntry ObjectStateEntry ObjectStateEntry ObjectStateEntry

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

Returns

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

Exceptions

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

Examples

The examples in this topic are based on the AdventureWorks 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");
    }
}
Dim orderId As Integer = 43680

Using context As New AdventureWorksEntities()
    Dim objectStateManager As ObjectStateManager = context.ObjectStateManager
    Dim stateEntry As ObjectStateEntry = Nothing

    Dim order = (From o In context.SalesOrderHeaders
        Where o.SalesOrderID = orderId
        Select o).First()

    ' Attempts to retrieve ObjectStateEntry for the given EntityKey. 
    Dim isPresent As Boolean = objectStateManager.TryGetObjectStateEntry(DirectCast(order, IEntityWithKey).EntityKey, stateEntry)
    If isPresent Then
        Console.WriteLine("The entity was found")
    End If
End Using

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();
    }
}
Private Shared Sub ApplyItemUpdates(ByVal originalItem As SalesOrderDetail, ByVal updatedItem As SalesOrderDetail)
    Using context As 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 Then
            ' 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)
        End If
        context.SaveChanges()
    End Using
End Sub

Remarks

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

TryGetObjectStateEntry(Object, ObjectStateEntry) TryGetObjectStateEntry(Object, ObjectStateEntry) TryGetObjectStateEntry(Object, ObjectStateEntry) 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 *  -> bool
Public Function TryGetObjectStateEntry (entity As Object, ByRef entry As ObjectStateEntry) As Boolean

Parameters

entity
Object Object Object Object

The Object to which the retrieved ObjectStateEntry belongs.

entry
ObjectStateEntry ObjectStateEntry ObjectStateEntry ObjectStateEntry

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

Returns

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.

Applies to