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ObjectContext.Refresh Method (RefreshMode, Object)

Updates an object in the object context with data from the data source.

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

public void Refresh(
	RefreshMode refreshMode,
	Object entity
)

Parameters

refreshMode
Type: System.Data.Objects.RefreshMode

One of the RefreshMode values that specifies which mode to use for refreshing the ObjectStateManager.

entity
Type: System.Object

The object to be refreshed.

ExceptionCondition
ArgumentNullException

collection is null.

ArgumentOutOfRangeException

refreshMode is not valid.

ArgumentException

collection is empty.

-or-

An object is not attached to the context.

Refresh has the dual purpose of allowing an object to be refreshed with data from the data source and being the mechanism by which conflicts can be resolved. For more information, see Saving Changes and Managing Concurrency (Entity Framework).

The order in which objects are refreshed is nondeterministic.

After the Refresh method is called, the object’s original values will always be updated with the data source value, but the current values might or might not be updated with the data source value. This depends on the RefreshMode. The StoreWins mode means that the object should be updated to match the data source values. The ClientWins value means that only the changes in the object context will be persisted, even if there have been other changes in the data source.

To ensure that an object has been updated by data source-side logic, you can call the Refresh method with the StoreWins value after you call the SaveChanges method.

This example is based on the Adventure Works Sales Model. The example tries to save changes, and this 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.SalesOrderHeaders.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());
    }
}

.NET Framework

Supported in: 4.5.2, 4.5.1, 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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