Change only edited columns

Question

In an application I am developing, when trying to update only the fields that were changed the Entity Framework is also changing the fields that do not need.

Repository code:

public void Update(T entity)
{
   m_Context.Entry(entity).State = EntityState.Modified;            
}

Controller code:

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit(BlogViewModel model)
{
   if (ModelState.IsValid)
   {
      using (var context = new UnitOfWork())
      {
         var blogDomain = Mapper.Map<BlogViewModel, Blog>(model);

         blogDomain.DateEdited = DateTime.Now;

         context.BlogRepository.Update(blogDomain);
         context.SaveChanges();

         return RedirectToAction("Index");
      }
   }

   return View(model);
}

I would like a help to solve this problem.

Answer 1

You can indicate to the Entity which properties will not have their status changed using the IsModified = false, follows an example:

public void Update(Classe minhaClasse)
{
    if (m_Context.Entry(minhaClasse).State == EntityState.Detached)
        m_Context.Set<Classe>().Attach(minhaClasse);

    m_Context.Entry(minhaClasse).State = EntityState.Modified;

    //Aqui é indicado que a propriedade nao deve ser alterada
     _context.Entry(minhaClasse).Property(p => p.DataCadastro).IsModified = false;

    m_Context.SaveChanges();   
}

_{I don’t know which architecture you are using and your model, so you may have to make adjustments to the example.}