1.常用

db.Entry(实体).State = EntityState.Modified;
db.SaveChanges();

2.指定更新

db.Configuration.ValidateOnSaveEnabled = false;
db.TUser.Attach(实体);
ObjectStateEntry stateEntry = ((IObjectContextAdapter)db).ObjectContext.ObjectStateManager.GetObjectStateEntry(实体);
stateEntry.SetModifiedProperty("字段1");
stateEntry.SetModifiedProperty("字段2");
db.SaveChanges();
db.Configuration.ValidateOnSaveEnabled = true;

3.指定更新(推荐!好用!)

TConsultant model = db.TConsultant.FirstOrDefault(t => t.ID == iID);
if (TryUpdateModel(model, new string[] { "Name", "Sex", "PhoneNuber", "CertificateNumber", "Email", "QQ", "Culture" }))
{
          db.SaveChanges();
          return Content("修改成功!");
}

4.

1. [HttpPost]  
2.         /// <summary>  
3.         /// 执行修改的代码  
4.         /// </summary>  
5.         /// <param name="model"></param>  
6.         /// <returns></returns>  
7.         public ActionResult Modify(BlogArticle model)  
8.         {  
9.             try  
10.             {  
11.                 //1.将实体对象 a.加入 EF 对象容器中，并 b.获取 伪包装类对象  
12.                 DbEntityEntry<BlogArticle> entry = db.Entry<BlogArticle>(model);  
13.                 //2.将包装类对象的状态设置为 unchanged  
14.                 entry.State = System.Data.EntityState.Unchanged;  
15.                 //3.设置 被改变的属性  
16.                 entry.Property(a => a.ATitle).IsModified = true;  
17.                 entry.Property(a => a.AContent).IsModified = true;  
18.                 entry.Property(a => a.ACate).IsModified = true;  
19.   
20.                 //4.提交到数据库 完成修改  
21.                 db.SaveChanges();  
22.                 //5.更新成功，则命令浏览器 重定向 到 /Home/List 方法  
23.                 return RedirectToAction("Index", "Home");  
24.             }  
25.             catch (Exception ex)  
26.             {  
27.                 return Content("修改失败~~~" + ex.Message);  
28.             }  
29.         }   

ASP.NET MVC + EF 更新的几种方式