为所有现有用户分配编号 [英] Assigning number for all existing users

问题描述

我在我的应用中注册了5个用户。我需要为所有人分配ramdom号码，但我不能



我尝试过：

I have register 5 users in my app. I need assigning ramdom number for all of them but I cant

What I have tried:

public ActionResult Test(User user )
        {
            
            Random rand = new Random();
            int numero = rand.Next(1, 10000);
            var model = new User();

            model.UserId = user.UserId;
            model.Nombre = user.Nombre;                     
            model.Codigo = numero;

            
            db.Users.Add(model);
            db.SaveChanges();
            return View(model);
            
        }

推荐答案

好的，如果你想要更新现有记录，你觉得怎么样？ db.Users.Add 呢？您的代码专门创建了一个新用户并将其保存到表中！



您必须从数据库中检索现有的用户对象，分配随机数然后将更改保存回数据库。

OK, if you're trying to update an existing record, what do you think db.Users.Add does? Your code is specifically creating a new user and saving it to the table!

You have to retrieve the existing user object(s) from the database, assign the random numbers to them, then save the changes back to the database.

Random rand = new Random();
var users = db.Users;

foreach (var user in users)
{
    // Assign a 4 digit PIN
    user.Codigo = rand.Next(1000, 10000);
}

db.SaveChanges();

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