Only update actually updated fields in Entity Framework

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开发者_如何学Python 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?

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.