Question

我有两个模型和一个联接表。我想使用相同的视图来编辑和创建新的采购订单，同时以相同的形式添加商品。

PurchaseOrder模型：

public class PurchaseOrder
{
    public int ID { get; set; }

    [Required]
    public string Requester { get; set; }

    public int WorkOrder { get; set; }

    [Required]
    public string WorkSite { get; set; }

    public string Equipment { get; set; }

    public string Operator { get; set; }

    public string Remarks { get; set; }

    public ICollection<PurchaseOrderItem> Items { get; set; }
}

项目模型：

public class Item
    {
        public int ID { get; set; }

        public string PartNumber { get; set; }
    [Required]
    public string Name { get; set; }

    public string Description { get; set; }

    [Required]
    public int Quantity { get; set; }

    public string Remarks { get; set; }

    public ICollection<PurchaseOrderItem> PurchaseOrders { get; set; }
}

加入表实体

    public class PurchaseOrderItem
{
    public int PurchaseOrderID { get; set; }
    public int ItemID { get; set; }
    public PurchaseOrder PurchaseOrder { get; set; }
    public Item Item { get; set; }
}

PurchaseOrdersController编辑：

public async Task<IActionResult> Edit(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var purchaseOrder = await _context.PurchaseOrders
                .Include(x => x.Items)
                    .ThenInclude(x => x.Item)
                .Where(x => x.ID == id)
                .AsNoTracking()
                .SingleOrDefaultAsync();

            if (purchaseOrder == null)
            {
                return NotFound();
            }

            return View(purchaseOrder);
        }

编辑帖子方法：

[HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(int id, PurchaseOrder order)
        {
            if (id != order.ID)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                try
                {
                    var po = _context.PurchaseOrders.FirstOrDefault(i => i.ID == order.ID);
                    po.Requester = order.Requester;
                    po.WorkOrder = order.WorkOrder;
                    po.WorkSite = order.WorkSite;
                    po.Equipment = order.Equipment;
                    po.Operator = order.Operator;
                    po.Remarks = order.Remarks;

                    _context.Update(po);

                    

                    foreach (var i in order.Items)
                    {
                        var item = _context.Items.FirstOrDefault(n => n.ID == i.Item.ID);
                        item.PartNumber = i.Item.PartNumber;
                        item.Name = i.Item.Name;
                        item.Description = i.Item.Description;
                        item.Quantity = i.Item.Quantity;
                        item.Remarks = i.Item.Remarks;

                        _context.Update(item);
                    }

                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {

                    if (!PurchaseOrderExists(order.ID))
                    {
                        return NotFound();

                    }

                    else
                    {
                        throw;
                    }
                }
                return RedirectToAction(nameof(Index));
            }

            return View(order);

        }

编辑视图

@model OrderTrackingApp.Models.PurchaseOrder

@{
    ViewData["Title"] = "Edit";
}

<h1>Edit</h1>

<h4>PurchaseOrder</h4>
<hr />
<div class="row">
    <div class="col-md-4">
        <form asp-action="Edit">
            <div asp-validation-summary="ModelOnly" class="text-danger"></div>
            <input type="hidden" asp-for="ID" />
            <div class="form-group">
                <label asp-for="Requester" class="control-label"></label>
                <input asp-for="Requester" class="form-control" />
                <span asp-validation-for="Requester" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="WorkOrder" class="control-label"></label>
                <input asp-for="WorkOrder" class="form-control" />
                <span asp-validation-for="WorkOrder" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="WorkSite" class="control-label"></label>
                <input asp-for="WorkSite" class="form-control" />
                <span asp-validation-for="WorkSite" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Equipment" class="control-label"></label>
                <input asp-for="Equipment" class="form-control" />
                <span asp-validation-for="Equipment" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Operator" class="control-label"></label>
                <input asp-for="Operator" class="form-control" />
                <span asp-validation-for="Operator" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Remarks" class="control-label"></label>
                <input asp-for="Remarks" class="form-control" />
                <span asp-validation-for="Remarks" class="text-danger"></span>
            </div>

            <div class="form-group">
                <label class="control-label">Order Items</label>
                <table>
                    <tbody>
                        @{ int i = 0;}
                        <tr>
                            @foreach (var OrderItem in Model.Items)
                            {
                                <td>
                                    <input type="hidden" value="OrderItem[@i].ItemID" asp-for="@OrderItem.ItemID"
                                           class="form-control" />
                                    <input type="text" value="OrderItem[@i].Item.PartNumber" asp-for="@OrderItem.Item.PartNumber" class="form-control" />
                                    <input type="text" value="OrderItem[@i].Item.Name" asp-for="@OrderItem.Item.Name" />
                                </td>
                                i++;
                            }
                        </tr>
                    </tbody>
                </table>
            </div>

            <div class="form-group">
                <input type="submit" value="Save" class="btn btn-primary" />
            </div>


        </form>

    </div>
</div>

    


<div>
    <a asp-action="Index">Back to List</a>
</div>

@section Scripts {
    @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}

我目前在编辑时遇到两个问题：

该项目的标签填充如下：OrderItem [0] .Item.Name代替Value
当代码到达foreachloop来迭代项目时，它将引发空异常。

Answer 1

您仅获得关于新添加的子项的名称，没有ID。并且未初始化子数据的关系表ID的返回值中返回的空值。

您可以按照适用性通过以下两种方式解决此问题：

直接从视图添加子行并更新模型中的ID，因此您数据中将始终具有ID，并且您不需要面部null ID 问题。
或者，您可能需要先添加子表的新值然后在保存更改之前手动在关系数据中使用新的ID。

Answer 2

问题是模型绑定，它基于name属性。更改如下代码：

@{ int i = 0;}
<tr>
    @foreach (var OrderItem in Model.Items)
    {
        <td>
            <input type="hidden" name="Items[@i].Item.ID" asp-for="@OrderItem.Item.ID"
                    class="form-control" />
            <input type="text" name="Items[@i].Item.PartNumber" asp-for="@OrderItem.Item.PartNumber" class="form-control" />
            <input type="text" name="Items[@i].Item.Name" asp-for="@OrderItem.Item.Name" class="form-control" />
        </td>
        i++;
    }
</tr>

实体框架核心中具有多对多关系的CRUD

2 个答案: