我是ASP的初学者。NET和我想在下面的问题你的帮助，我正在开发一个屏幕，我在那里购买，我有队列，使释放的发票，这个发票有几个项目，但我想目前在一个列表中的索引页，使用foreach这个项目，但当我添加foreach我有一个错误，我会离开这里的代码。
我的模特

namespace SysComm.Models
{
    public class Purchases
    {
        [Key]
        public int PurchaseId { get; set; }

        [Required]
        public DateOnly PurcahseDate { get; set; }

        [Required]
        [DisplayName("Invoice Nº.")]
        [StringLength(100)]
        public string PurchaseInvoice { get; set; }

        [DisplayName("Supplier")]
        public int SupplierId { get; set; }
        [ForeignKey("SupplierId")]
        [ValidateNever]

        [Required]
        public Suppliers Suppliers { get; set; }

        [Required]
        public DateOnly PurchaseDateDue { get; set; }

        [DisplayName("BarCode")]
        public string? PurchaseBarCode { get; set; }

        [DisplayName("Group Name")]
        public int GroupId { get; set; }
        [ForeignKey("GroupId")]
        [ValidateNever]

        [Required]
        public Groups Groups { get; set; }

        [DisplayName("Product Name")]
        public int ProductId { get; set; }
        [ForeignKey("ProductId")]
        [ValidateNever]

        [Required]
        public Products Products { get; set;}

        [Required]
        [DisplayName("Quantity")]
        [Column(TypeName ="decimal(18,4)")]
        public decimal PurchaseQuantity { get; set; }

        [Required]
        [DisplayName("Purchase Price")]
        [Column(TypeName = "decimal(18,2)")]
        public decimal PurchaseUnityCost { get; set; }

        [Required]
        [DisplayName("VAT Percentual")]
        [Column(TypeName ="decimal(18,4)")]
        public decimal PurchaseVatPerc { get; set; }

        [Required]
        [DisplayName("VAT Value")]
        [Column(TypeName ="decimal(18,m2)")]
        public decimal PurchaseVatValue { get; set;}

        [Required]
        [DisplayName("Total Product")]
        [Column(TypeName ="decimal(18,2)")]
        public decimal PurchaseTotal { get; set; }
    }
}

我的控制器：

public class PurchaseController : Controller
{
    private readonly IUnitOfWork _unitOfWork;

    public PurchaseController(IUnitOfWork unitOfWork)
    {
        _unitOfWork = unitOfWork;
    }

    public IActionResult Index()
    {
        List<Purchases> objPurchaseList = _unitOfWork.Purchase.GetAll().ToList();
        
        return View(objPurchaseList);
    }

    //GET
    public IActionResult Create()
    {
        IEnumerable<SelectListItem> GroupList = _unitOfWork.Group
            .GetAll().Select(u => new SelectListItem
            {
                Text = u.GroupName,
                Value = u.GroupId.ToString()
            });

        ViewBag.GroupList = GroupList;

        IEnumerable<SelectListItem> SupplierList = _unitOfWork.Supplier
            .GetAll().Select(u => new SelectListItem
            {
                Text = u.SupplierName,
                Value = u.SupplierId.ToString()
            });

        ViewBag.SupplierList = SupplierList;

        IEnumerable<SelectListItem> ProductList = _unitOfWork.Product
            .GetAll().Select(u => new SelectListItem
            {
                Text = u.ProductName,
                Value = u.ProductId.ToString()
            });

        ViewBag.ProductList = ProductList;

        return View();
    }
}

我的观点

@model Purchases

<form method="post">
    <div class="border p-3 mt-4 row">
        <div class="row pb-2">
            <h2 class="text-primary">Create New Purchase</h2>
            <hr />
        </div>
        <div class="mb-3 col-2">
            <label asp-for="PurcahseDate"></label>
            <input asp-for="PurcahseDate" class="form-control" autofocus="autofocus" style="text-transform:capitalize" />
            <span asp-validation-for="PurcahseDate" class="text-danger"></span>
        </div>
        <div class="mb-3 col-8">
            <label asp-for="SupplierId"></label>
            <select asp-for="SupplierId" asp-items="ViewBag.SupplierList" class="form-select">
                <option disabled selected>--Select Supplier--</option>
            </select>
            <span asp-validation-for="SupplierId" class="text-danger"></span>
        </div>
        <div class="mb-3 col-2">
            <label asp-for="PurchaseDateDue"></label>
            <input asp-for="PurchaseDateDue" class="form-control" style="text-transform:uppercase" />
            <span asp-validation-for="PurchaseDateDue" class="text-danger"></span>
        </div>
        <div class="mb-3 col-4">
            <label asp-for="PurchaseBarCode"></label>
            <input asp-for="PurchaseBarCode" class="form-control" style="text-transform:capitalize" />
            <span asp-validation-for="PurchaseBarCode" class="text-danger"></span>
        </div>
        <div class="mb-3 col-8">
            <label asp-for="GroupId"></label>
            <select asp-for="GroupId" asp-items="ViewBag.GroupList" class="form-select">
                <option disabled selected>--Select Group--</option>
            </select>
            <span asp-validation-for="GroupId" class="text-danger"></span>
        </div>
        <div class="mb-3">
            <label asp-for="ProductId"></label>
            <select asp-for="ProductId" asp-items="ViewBag.ProductList" class="form-select">
                <option disabled selected>--Select Prodcut--</option>
            </select>
            <span asp-validation-for="ProductId" class="text-danger"></span>
        </div>
        <div class="mb-3 col-2">
            <label asp-for="PurchaseQuantity"></label>
            <input asp-for="PurchaseQuantity" class="form-control"/>
            <span asp-validation-for="PurchaseQuantity" class="text-danger"></span>
        </div>
        <div class="mb-3 col-2">
            <label asp-for="PurchaseUnityCost"></label>
            <input asp-for="PurchaseUnityCost" class="form-control"/>
            <span asp-validation-for="PurchaseUnityCost" class="text-danger"></span>
        </div>
        <div class="mb-3 col-2">
            <label asp-for="PurchaseVatPerc"></label>
            <input asp-for="PurchaseVatPerc" class="form-control"/>
            <span asp-validation-for="PurchaseVatPerc" class="text-danger"></span>
        </div>
        <div class="mb-3 col-2">
            <label asp-for="PurchaseVatValue"></label>
            <input asp-for="PurchaseVatValue" class="form-control"/>
            <span asp-validation-for="PurchaseVatValue" class="text-danger"></span>
        </div>
        <div class="mb-3 col-4">
            <label asp-for="PurchaseTotal"></label>
            <input asp-for="PurchaseTotal" class="form-control" />
            <span asp-validation-for="PurchaseTotal" class="text-danger"></span>
        </div>
        <div class="mb-3 col-6 col-md-3">
            <button type="submit" class="btn btn-primary form-control">Create</button>
        </div>
        <div class="mb-3 col-6 col-md-3">
            <a asp-controller="Purchase" asp-action="Index" class="btn btn-secondary form-control">
                Back to List
            </a>
        </div>
    </div>

    <table class="table table-bordered table-striped" style="width:100%">
        <thead>
            <tr>
                <th>
                    Date
                </th>
                <th>
                    Invoice Nº
                </th>
                <th>
                    Supplier Name
                </th>
                <th>
                    Total Invoice
                </th>
                <th>
                    Action
                </th>
            </tr>
        </thead>
        <tbody>
            @foreach (var obj in Model)* => HERE IS THE ERROR*
            {
                <tr>
                    <td width="10%">
                        @obj.PurcahseDate
                    </td>
                    <td width="100%">
                        @obj.PurchaseInvoice
                    </td>
                    <td width="40%">
                        @obj.SupplierId
                    </td>
                    <td width="20%">
                        @Model.Sum(u=> u.PurchaseTotal)
                    </td>
                    <td width="20%">
                        <div class="w-75 btn-group" role="group">
                            <a asp-controller="Purchase" asp-action="Edit" style="width:120px" asp-route-id="@obj.PurchaseId"
                               class="btn btn-primary mx-2"> <i class="bi bi-pencil-square"></i> Edit</a>
                            <a asp-controller="Purchase" asp-action="Delete" style="width:125px" asp-route-id="@obj.PurchaseId"
                               class="btn btn-danger mx-2"> <i class="bi bi-trash-fill"></i> Delete</a>
                        </div>
                    </td>
                </tr>
            }
        </tbody>
    </table>

</form>

@section Scripts {
    @{
        <partial name="_ValidationScriptsPartial" />
    }
}

错误发生在foreach循环中。有人能帮忙吗？谢谢大家。