Persists all updates to the data source and resets change tracking in the object context.
(in System.Data.Entity.dll)
Visual Basic (Declaration)
Public Function SaveChanges As Integer
Dim instance As ObjectContext
Dim returnValue As Integer
returnValue = instance.SaveChanges()
public:
int SaveChanges()
public function SaveChanges() : int
This method is to the same as calling SaveChanges(Boolean) and passing a value of true.
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. For more information, see Saving Changes and Managing Concurrency (Entity Framework).
SaveChanges 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 value, and then calling SaveChanges 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. This example tries to save changes, which may cause a concurrency conflict. Then, it demonstrates how to resolve the concurrency conflict by refreshing the object context before re-saving changes.
Using context As New AdventureWorksEntities()
Try
' Perform an operation with a high-level of concurrency.
' Change the status of all orders without an approval code.
Dim orders As ObjectQuery(Of SalesOrderHeader) = _
context.SalesOrderHeader.Where( _
"it.CreditCardApprovalCode IS NULL").Top("100")
For Each order As SalesOrderHeader In orders
' Reset the order status to 4 = Rejected.
order.Status = 4
Next
Try
' Try to save changes, which may cause a conflict.
Dim num As Integer = context.SaveChanges()
Console.WriteLine("No conflicts. " + _
num.ToString() + " updates saved.")
Catch ex As 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.")
End Try
For Each order As SalesOrderHeader In orders
Console.WriteLine("Order ID: " + order.SalesOrderID.ToString() _
+ " Order status: " + order.Status.ToString())
Next
Catch ex As UpdateException
Console.WriteLine(ex.ToString())
End Try
End Using
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
Reference
Other Resources