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ObjectContext.SaveChanges Method (Boolean)

Persists all updates to the data source and optionally resets change tracking in the object context.

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

public int SaveChanges(
	bool acceptChangesDuringSave
)

Parameters

acceptChangesDuringSave
Type: System.Boolean

This parameter is needed for client-side transaction support. If true, the change tracking on all objects is reset after SaveChanges(Boolean) finishes. If false, you must call the AcceptAllChanges method after SaveChanges(Boolean).

Return Value

Type: System.Int32
The number of objects in an Added, Modified, or Deleted state when SaveChanges was called.

ExceptionCondition
InvalidOperationException

The service adapter is null.

OptimisticConcurrencyException

An optimistic concurrency violation has occurred.

To ensure that objects on the client have been updated by data source-side logic, you can call the Refresh method with the StoreWins value after you call SaveChanges. The SaveChanges method operates within a transaction. SaveChanges will roll back that transaction and throw an exception if any of the dirty ObjectStateEntry objects cannot be persisted.

If an optimistic concurrency violation has occurred, an OptimisticConcurrencyException is thrown. You can resolve an optimistic concurrency violation by catching it, calling the Refresh method with the StoreWins or ClientWins values, and then calling the SaveChanges method again. For more information, see How to: Manage Data Concurrency in the Object Context (Entity Framework).

This example is based on the Adventure Works Sales Model. The example tries to save changes, which may cause a concurrency conflict. Then it shows how to resolve the concurrency conflict by refreshing the object context before re-saving changes.

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    try
    {
        // Perform an operation with a high-level of concurrency. 
        // Change the status of all orders without an approval code.
        ObjectQuery<SalesOrderHeader> orders =
            context.SalesOrderHeader.Where(
            "it.CreditCardApprovalCode IS NULL").Top("100");

        foreach (SalesOrderHeader order in orders)
        {
            // Reset the order status to 4 = Rejected.
            order.Status = 4;
        }
        try
        {
            // Try to save changes, which may cause a conflict. 
            int num = context.SaveChanges();
            Console.WriteLine("No conflicts. " +
                num.ToString() + " updates saved.");
        }
        catch (OptimisticConcurrencyException)
        {
            // Resolve the concurrency conflict by refreshing the  
            // object context before re-saving changes. 
            context.Refresh(RefreshMode.ClientWins, orders);

            // Save changes.
            context.SaveChanges();
            Console.WriteLine("OptimisticConcurrencyException "
            + "handled and changes saved");
        }

        foreach (SalesOrderHeader order in orders)
        {
            Console.WriteLine("Order ID: " + order.SalesOrderID.ToString()
                + " Order status: " + order.Status.ToString());
        }
    }
    catch (UpdateException ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

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

.NET Framework

Supported in: 3.5 SP1

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