Can I "undo" a LINQ to SQL update?

Question

In LINQ-to-SQL if I update an object in the context but haven't called SubmitChanges, is there a way to "undo" or abandon that update so that the changes won't get submitted when I eventually call SubmitChanges? For example, if I've updated several objects and then decide I want to abandon the changes to one of them before submitting.

Part 2: same question for Entity Framework, v3.5

Answer 1

Check out Marc's answer at
http://stackoverflow.com/questions/456895/howto-undo-changeset-in-linqtosql

Answer 2

Both LINQ to SQL and Entity Framework will use the same call (assuming you still have the active Context):

_dbContext.Refresh(RefreshMode.OverwriteCurrentValues, yourObj);

A more appropriate way would be to treat the Context as a Unit of Work, in which case you would no longer have an active context when refreshing the object. You would simply dispose of the object you're using currently and get a fresh copy from a new context.

Answer 3

I think you can use the .GetOriginalEntityState(yourEntity) to retrieve the original values. Then set your updated entity back to the original

dim db as new yourDataContext
//get entity
dim e1 as yourEntity = (from x in db.table1).take(1)
//update entity
e1.someProperty = 'New Value'
//get original entity
dim originalEntity = db.table1.getOrignalEntityState(e1)
e1 = originalEntity
db.submitChanges()

Very pseudo-code but I think it conveys the right idea. Using this method, you could also just undo one or more property changes without refreshing the entire entity.