首先在代码中高效地更新多个记录

本文关键字:更新 记录 高效 代码 | 更新日期: 2023-09-27 18:05:41

在一个操作中有以下场景,我想更新给定购物车中所有商品的数量。我张贴回数组到我的购物车项目的控制器,并希望更新数量,因为用户已经更新了它们。我怎样才能做到这一点呢?这就是我现在的处境。

这是购物车的视图

@model SeniorProjectMVC.Models.ViewModels.CartViewModel
@{
    ViewBag.Title = "Index";
    Layout = "~/Views/Shared/_Layout.cshtml";
}
<h3>Your cart</h3>
@*<p>
    @Html.ActionLink("Create New", "Create")
</p>*@  
<div class="row header-row">
    <div class="large-1 columns">
        <h4> Quantity</h4>
    </div>
    <div class="large-5 columns text-center">
       <h4>Name</h4> 
    </div>
    <div class="large-1 columns">
      <h4>Price</h4>  
    </div>
    <div class="large-2 columns">
        <h4>In stock</h4>
    </div>
    <div class="large-3 columns"></div>
</div>
@{ 
    int CurrentIndex = 1;
}
@for (int i = 0; i < Model.CartArray.Length; i++)
{
    <div class="@(CurrentIndex % 2 == 0 ? "row primary-row" : "row alternate-row")">
        <div class="large-1 columns">
            @Html.EditorFor( m => m.CartArray[i].Quantity)
        </div>
        <div class="large-5 columns text-center">
            @Html.DisplayFor(m => m.CartArray[i].Sku.Product.Name)
        </div>
        <div class="large-1 columns">
            @*@Html.DisplayFor(m => m.CartArray[i].Sku.Product.Price)*@
            @String.Format("{0:c}", (Model.CartArray[i].Sku.Product.Price * Model.CartArray[i].Quantity))
        </div>
        <div class="large-2 columns">
            @( Model.CartArray[i].Sku.Quantity > 0 ? "In Stock" : "Out of stock")
        </div>
        <div class="large-3 columns">
            <ul class="button-group">
                @*<li class="button">@Html.ActionLink("Edit", "Edit", new { id = Model.CartArray[i].ID }, new { @class = "button primary" }) </li>*@
                <li class="button">@Html.ActionLink("Remove", "Remove", new { id = Model.CartArray[i].ID }, new { @class = "button primary" })</li>
            </ul>
            @*@Html.ActionLink("Details", "Details", new { id = item.ID }, new { @class = "button primary" }) |*@
        </div>
    </div>
    { CurrentIndex = CurrentIndex + 1; }
}
<div clsas="row">
    <div class="large-offset-8 columns">
        <h5 class="inline">Subtotal:</h5><h4 class="inline">@(Model.CartArray.Sum(p => (p.Sku.Product.Price * p.Quantity)).ToString("c"))</h4>
    </div>
</div>
<div class="row">
    <div class="medium-offset-8 medium-4 columns">
        <ul class="button-group">
            <li class="button">@Html.ActionLink("Update Quantities", "UpdateQuantities", "Cart", new { array = Model.CartArray }, new { @class = "button primary large" })</li>
            @if (Request.IsAuthenticated && User.Identity.IsAuthenticated)
            {
                <li class="button">@Html.ActionLink("Checkout", "Address", "Checkout", null, new { @class = "button primary large" })</li>
            }
            else
            {
                <li class="button secondary">You must sign in to checkout</li>
            }
        </ul>   
    </div>
</div>

这是我想要将数量发送回控制器的操作,然后更新我的数据库上下文类。我不知道如何或什么是实现这一目标的最有效的方法。

public ActionResult UpdateQuantities(Models.ViewModels.CartViewModel cartModel)
        {
            for (int i = 0; i < cartModel.CartArray.Length; i++)
            {
                //either update each record, or build a list to do one mass update.
                //This is where I am stuck
            }
            return View();
        }

首先在代码中高效地更新多个记录

您应该能够像这样:

public ActionResult UpdateQuantities(Models.ViewModels.CartViewModel cartModel)
{
    // instantiate your database context if it's not already done
    using (var db = new Context())
    {
        for (int i = 0; i < cartModel.CartArray.Length; i++)
        {
            // update your records one at a time
            db.YourItems.Where(i => <your_criteria>).Member = NewValue;
        }
        // commit your changes only once at the end
        db.SaveChanges();
        return View();
    }

根据你的模型数据的结构,你也可以像这样替换上面的for循环:

var items = db.YourItems.ToList();
items.ForEach(i => i.Member = cartModel.CartArray[i.Id].NewValue);

或者如果你需要更新几个属性:

items.ForEach(i => {
    i.Member1 = cartModel.CartArray[i.Id].Value1;
    i.Member2 = cartModel.CartArray[i.Id].Value2;
};