How to update not every fields of an object using Entity Framework and EntityState.Modified

Question

I need to update all fields except property1 and property2 for the given entity object.
Having this code:

    [HttpPost]     public ActionResult Add(object obj)     {         if (ModelState.IsValid)         {                 context.Entry(obj).State = System.Data.EntityState.Modified;                  context.SaveChanges();                         }         return View(obj);     } 

How to change it to add an exception to obj.property1 and obj.property2 for not being updated with this code?

Answer 1

Let's assume that you have a collection of the properties to be excluded:

var excluded = new[] { "property1", "property2" }; 

With EF5 on .NET 4.5 you can do this:

var entry = context.Entry(obj); entry.State = EntityState.Modified; foreach (var name in excluded) {     entry.Property(name).IsModified = false; } 

This uses a new feature of EF5 on .NET 4.5 which allows a property to be set as not modified even after it has been previously set to modified.

When using EF 4.3.1 or EF5 on .NET 4 you can do this instead:

var entry = context.Entry(obj); foreach (var name in entry.CurrentValues.PropertyNames.Except(excluded)) {     entry.Property(name).IsModified = true; }