MVC Entity Framework：更新表中多条记录的字段

Question

我很难确定这是否只是一个设计问题和/或如何从编码角度解决以下情况：

在我的项目中，我允许用户添加多个送货地址。显然，其中之一应该是送货地址。但是，我想提供由用户自行决定更改此设置的可能性。 因此，我使用名为“IsDefaultShippingAddress”（布尔）的列存储了送货地址。我想做的是，当用户选择送货地址作为默认地址时，模型将为该列传递“true”。

现在，如果用户有一个现有的送货地址被选为默认地址，并想添加一个新的默认送货地址（或将现有送货地址提升为默认地址），我自然会以同一个用户在同一个表中有两个（多个）记录的场景，其中“IsDefaultShippingAddress”为“true” - 但我希望它只是一个地址（最新提升的地址），根据术语“默认”的性质。

因此我的问题是，如何确保所有符合特定条件（用户 ID）的记录都更新为 'IsDefaultShippingAddress' 'false'，而新提升的送货地址（同一张表中的单独行）被设置为 @ 987654322@?

这是我的控制器代码，这是未解决问题的代码：

// POST: /Manage/EditShippingAddress
    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult EditShippingAddress([Bind(Include = "ID,UserID,IsDefaultShippingAddress,ShippingAddressCompanyName,ShippingAddressFirstName,ShippingAddressLastName,ShippingAddressAdditional,ShippingAddressStreet,ShippingAddressNumber,ShippingAddressZIP,ShippingAddressCity,ShippingAddressState,ShippingAddressCountry,ShippingInstructions,UpdatedLatitude,UpdatedLongitude,UpdatedLocation")] ShippingAddresses model)
    {
        // define variables
        var userID = User.Identity.GetUserId();
        DateTime nowUTC = DateTime.Now.ToUniversalTime();
        DateTime nowLocal = DateTime.Now.ToLocalTime();
        // pass first name to viewbag for personalization
        ViewBag.Personalization = UserManager.FindById(userID).FirstName.ToString();
        if (ModelState.IsValid)
        {
            DATADB.Entry(model).State = System.Data.Entity.EntityState.Modified;
            DATADB.SaveChanges();
            return RedirectToAction("ShippingAddresses");
        }
        return View(model);
    }

Answer 1

将此代码放在您的 if 语句之前。

我还没有执行代码。可能有一些语法错误，但你明白了。

if (model.IsDefaultShippingAddress)
{
   var addresses = DATADB.ShippingAddresses.Where(address => address.UserId == userId);

   addresses.ForEach(address => address.IsDefaultShippingAddress = false);
}
DATADB.SaveChanges();

Answer 2

感谢 Selçuk - 在您的帮助下，我走上了正确的道路。我有点曲折，现在我有了我的解决方案：

public ActionResult EditShippingAddress([Bind(Include = "ID,UserID,IsDefaultShippingAddress,ShippingAddressCompanyName,ShippingAddressFirstName,ShippingAddressLastName,ShippingAddressAdditional,ShippingAddressStreet,ShippingAddressNumber,ShippingAddressZIP,ShippingAddressCity,ShippingAddressState,ShippingAddressCountry,ShippingInstructions,UpdatedLatitude,UpdatedLongitude,UpdatedLocation")] ShippingAddresses model)
    {
        // define variables
        var userID                                                  = User.Identity.GetUserId();
        DateTime nowUTC                                             = DateTime.Now.ToUniversalTime();
        DateTime nowLocal                                           = DateTime.Now.ToLocalTime();
        // pass first name to viewbag for personalization
        ViewBag.Personalization                                     = UserManager.FindById(userID).FirstName.ToString();
        if (ModelState.IsValid)
        {
            if (model.IsDefaultShippingAddress)
            {
                var addresses = DATADB.ShippingAddressList
                    .Where(a => a.UserID                            == userID);
                var address = DATADB.ShippingAddressList
                    .Where(a => a.ID                                == model.ID);
                addresses.ForEach(a => a.IsDefaultShippingAddress   = false);
                address.ForEach(a => a.IsDefaultShippingAddress     = model.IsDefaultShippingAddress);
                address.ForEach(a => a.ShippingAddressCompanyName   = model.ShippingAddressCompanyName);
                address.ForEach(a => a.ShippingAddressFirstName     = model.ShippingAddressFirstName);
                address.ForEach(a => a.ShippingAddressLastName      = model.ShippingAddressLastName);
                address.ForEach(a => a.ShippingAddressAdditional    = model.ShippingAddressAdditional);
                address.ForEach(a => a.ShippingAddressStreet        = model.ShippingAddressStreet);
                address.ForEach(a => a.ShippingAddressNumber        = model.ShippingAddressNumber);
                address.ForEach(a => a.ShippingAddressZIP           = model.ShippingAddressZIP);
                address.ForEach(a => a.ShippingAddressCity          = model.ShippingAddressCity);
                address.ForEach(a => a.ShippingAddressState         = model.ShippingAddressState);
                address.ForEach(a => a.ShippingAddressCountry       = model.ShippingAddressCountry);
                address.ForEach(a => a.ShippingInstructions         = model.ShippingInstructions);
            }
            DATADB.SaveChanges();
            // track user activity: post method includes activity name and timestamp along with location
            var SUCCESS                                             = new UserActivities
            {
                UserID                                              = userID,
                ActivityName                                        = "EditShippingAddress_Success",
                ActivityTimeStampUTC                                = nowUTC,
                ActivityLatitude                                    = model.UpdatedLatitude,
                ActivityLongitude                                   = model.UpdatedLongitude,
                ActivityLocation                                    = model.UpdatedLongitude
            };
            DATADB.UserActivityList.Add(SUCCESS);
            DATADB.SaveChanges();
            return RedirectToAction("ShippingAddresses");
        }
        var FAILURE                                                 = new UserActivities
        {
            UserID                                                  = userID,
            ActivityName                                            = "EditShippingAddress_Failure",
            ActivityTimeStampUTC                                    = nowUTC,
            ActivityLatitude                                        = model.UpdatedLatitude,
            ActivityLongitude                                       = model.UpdatedLongitude,
            ActivityLocation                                        = model.UpdatedLongitude
        };
        DATADB.UserActivityList.Add(FAILURE);
        DATADB.SaveChanges();
        return View(model);
    }