Question

这是我的控制器操作方法Calculate

public ActionResult Calculate(List<BOM> bl )
{
    ViewBag.Category = new SelectList(db.Category, "ID", "Type");
    if (ModelState.IsValid)
    {
        foreach (var i in bl)
        {
            db.BOM.Add(i);
        }                
        db.SaveChanges();
    }
    return View();
}

和行动方法的视图

@model List<My_Inventory.Models.BOM>

@{
    ViewBag.Title = "Calculate";
    Layout = "~/Views/Shared/_Layout.cshtml";
} 

@using (Html.BeginForm())
{
    <fieldset>
        @Html.AntiForgeryToken()

        <table class="table">
            <tr>
                <th>@Html.LabelFor(model => model.Category, htmlAttributes: new { @class = "category" })</th>
                <th>@Html.LabelFor(model => model.Make, htmlAttributes: new { @class = "brand" })</th>
                <th>@Html.LabelFor(model => model.Item, htmlAttributes: new { @class = "Category" })</th>
                <th>@Html.LabelFor(model => model.Quantity, htmlAttributes: new { @class = "PQuantity" })</th>
                <th>@Html.LabelFor(model => model.Unit_Cost, htmlAttributes: new { @class = "Unit" })</th>
                <th>@Html.LabelFor(model => model.Total_Cost, htmlAttributes: new { @class = "Total" })</th>
            </tr>


            @for (int i = 0; i < 20; i++)
            {
                <tr>
                    <td>
                        @Html.DropDownListFor(model => model.Category, ViewBag.Category as SelectList, "Select", new { @id = "ddlSelect" + i, @class = "category", onchange = "Getoption(" + i + ");" })
                    @Html.ValidationMessageFor(model => model.Category, "", new { @class = "text-danger" })
                </td>
                <td>
                    @Html.DropDownListFor(model => model.Make, new SelectList(Enumerable.Empty<SelectListItem>(), "Value", "Text"), "Select", new { @id = "ddlsub" + i, @class = "brand", onchange = "GetProducts(" + i + ");" })
                    @Html.ValidationMessageFor(model => model.Make, "", new { @class = "text-danger" })
                </td>

                <td>
                    @Html.DropDownListFor(model => model.Item, new SelectList(Enumerable.Empty<SelectListItem>(), "Value", "Text"), "Select", new { @id = "ddlProduct" + i, @class = "Product" })
                    @Html.ValidationMessageFor(model => model.Item, "", new { @class = "text-danger" })
                </td>

                <td>
                    @Html.TextBoxFor(model => model.Quantity, new { @id = "TextQuantity" + i, @class = "PQuantity", onblur = "Calculatecost(" + i + ");" })
                    @Html.ValidationMessageFor(model => model.Quantity, "", new { @class = "text-danger" })
                </td>
                <td>
                    @Html.LabelFor(model => model.Unit_Cost, "UnitCost", new { @id = "Ucost" + i, @class = "Unit" })
                    @Html.ValidationMessageFor(model => model.Quantity, "", new { @class = "text-danger" })
                </td>
                <td>
                    @Html.LabelFor(model => model.Total_Cost, "TotalCost", new { @id = "TotalCost" + i, @class = "" })
                    @Html.ValidationMessageFor(model => model.Quantity, "", new { @class = "text-danger" })
                </td>

                    </tr>
            }
        </table>
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="Create" class="btn btn-default" />
        </div>

我正在将多行数据从视图传递到控制器，以便将它们保存到数据库中，但它会抛出错误＆＃34;对象引用未设置为对象的实例。＆＃34; 有什么建议......怎么回事？

Answer 1

首先，您没有将模型传递给Controller中的视图，它应该是return View(bl);而不是简单的return View();

其次，既然你没有将它传递给你的View，它就不会被设置，因此Model是null。

第三，您传递List作为模型，并在视图中将其作为单个对象访问。请检查您的代码并重新发布。

如何将多行数据从视图传递到控制器

1 个答案: