Question

I have models with datetime fields.

My code is working with models setting this reseting this fields to now.
But I don’t want “setting” now, but “saving” now: i.e. if I set field1 = now [0:00:00], then, 10s. later field2 = now [0:00:10] and then, 10s. later, I execute SaveChanges() I’d like to have both field set to 0:00:20 (saving time).

Edit: code example:

var context = new SomeEntities();
SomeModel model = context.GetSomeModel(...);
// SomeModel has two DateTime fields: dt1 and dt2
model.dt1 = SavingDateTimeNow(); // .... 13:42:00
// some code, i.e. Sleep(TimeSpan.FromSeconds(10));
model.dt2 = SavingDateTimeNow(); // .... 13:42:10
// again 10s. code
context.SaveChanges(); // .... 13:42:20

Edit2: More complex example:

var context = new SomeEntities();
SomeModel model = context.GetSomeModel(...);
// SomeModel has two DateTime fields: dt1 and dt2
if(someComplexCondition)model.dt1 = SavingDateTimeNow(); // .... 13:42:00
// some code from which I would know if someOtherComplexCondition is true
if(someOtherComplexCondition)model.dt2 = SavingDateTimeNow(); // .... 13:42:10
// again 10s. code
// much more code here
context.SaveChanges(); // .... 13:42:20

I want both (dt1 and dt2) to be set to … 13:42:20, not 13:42:00 and 13:42:10

Edit3: Simplest example: I would like it to work just like django’s fields with auto_now=True.

Answer 1

I found solution which isn’t perfect (if you find better one, please, post it here).
Here is full article: Dave Dunkin’s blog: Automatic Timestamping for Entity Framework

The idea is to:

1. Create interface for models which needs this feature
2. Implement infreface
3. Create methods in Entitywhich would go through all modified entities, check for entitites implementng interface and modify its datetime fields (it could be done by method in this interface)
4. Add this methods to SavingChanges event in Entity