c# - 实体框架5更新记录(Entity Framework 5 Updating a Record)

Question

I have been exploring different methods of editing/updating a record within Entity Framework 5 in an ASP.NET MVC3 environment, but so far none of them tick all of the boxes I need.

(我一直在探索在ASP.NET MVC3环境中编辑/更新实体框架5中的记录的不同方法，但到目前为止，它们都没有勾选我需要的所有框。)

I'll explain why.

(我会解释原因。)

I have found three methods to which I'll mention the pros and cons:

(我找到了三种方法，我将提到它的优点和缺点：)

Method 1 - Load original record, update each property

(方法1 - 加载原始记录，更新每个属性)

var original = db.Users.Find(updatedUser.UserId);

if (original != null)
{
    original.BusinessEntityId = updatedUser.BusinessEntityId;
    original.Email = updatedUser.Email;
    original.EmployeeId = updatedUser.EmployeeId;
    original.Forename = updatedUser.Forename;
    original.Surname = updatedUser.Surname;
    original.Telephone = updatedUser.Telephone;
    original.Title = updatedUser.Title;
    original.Fax = updatedUser.Fax;
    original.ASPNetUserId = updatedUser.ASPNetUserId;
    db.SaveChanges();
}    

Pros

(优点)

• Can specify which properties change

  (可以指定更改哪些属性)

• Views don't need to contain every property

  (视图不需要包含每个属性)

Cons

(缺点)

• 2 x queries on database to load original then update it

  (在数据库上进行2次查询以加载原始数据然后更新它)

Method 2 - Load original record, set changed values

(方法2 - 加载原始记录，设置更改的值)

var original = db.Users.Find(updatedUser.UserId);

if (original != null)
{
    db.Entry(original).CurrentValues.SetValues(updatedUser);
    db.SaveChanges();
}

Pros

(优点)

• Only modified properties are sent to database

  (仅将已修改的属性发送到数据库)

Cons

(缺点)

• Views need to contain every property

  (视图需要包含每个属性)

• 2 x queries on database to load original then update it

  (在数据库上进行2次查询以加载原始数据然后更新它)

Method 3 - Attach updated record and set state to EntityState.Modified

(方法3 - 附加更新的记录并将状态设置为EntityState.Modified)

db.Users.Attach(updatedUser);
db.Entry(updatedUser).State = EntityState.Modified;
db.SaveChanges();

Pros

(优点)

• 1 x query on database to update

  (1 x查询数据库以进行更新)

Cons

(缺点)

• Can't specify which properties change

  (无法指定更改哪些属性)

• Views must contain every property

  (视图必须包含每个属性)

Question

(题)

My question to you guys;

(我向你们提问;)

is there a clean way that I can achieve this set of goals?

(有没有一种干净的方式可以达到这套目标？)

• Can specify which properties change

  (可以指定更改哪些属性)

• Views don't need to contain every property (such as password!)

  (视图不需要包含每个属性（例如密码！）)

• 1 x query on database to update

  (1 x查询数据库以进行更新)

I understand this is quite a minor thing to point out but I may be missing a simple solution to this.

(我明白这是一个很小的事情要指出，但我可能错过了一个简单的解决方案。)

If not method one will prevail ;-)

(如果不是方法一将占上风;-))

  ask by Stokedout translate from so

Answer 1

You are looking for:

(您正在寻找：)

db.Users.Attach(updatedUser);
var entry = db.Entry(updatedUser);
entry.Property(e => e.Email).IsModified = true;
// other changed properties
db.SaveChanges();