Only update actually updated fields in Entity Framework

Question

Quite a common use case, it seems, is when re-populating an object from a form is to go

myobj.Name = "textbox value";
myobj.Content = "textbox content";

But, name may not have changed, it may only be a change to the content textbox.

The problem is that entity framework treats Name as changed just because I've set it's value, regardless of whether I've set exactly the same value or not.

Ideally, I would like EF to only mark things as changed if they genuinely have changed. Is this possible?

Answer 1

What version of EF are you using?

Try this - go to definition of Name property in the entity, and see if it has a check in it's setter like:

set
{
    if (Name != value)
    ...
}

If it doesn't, alter the t4 templates (if you're using EF 4.0) and add manually.

Otherwise, I don't think there's a cheap way of 'unchanging' the changed property.

Edit: To create T4 from existing model, right click your model, choose Add code generation items, and choose EntityObject generator. This will create a tt file that you can run by issuing a save command (you'll get a prompt if you want to allow it to run). When saved, it will generate a file that's exactly the same as the file generated by edmx model. Now, you just need to locate the part where it generates a property set. The tt can be intimidating at first look, but it really pays off learning it... there's an extension for coloring the text of t4 - you can find it in extension manager and it's free.