EFCore中的顯式加載隨機加載.Include()

我有一個 .NET 5 專案Index頁面，其中包含表中所有行的表Contracts，每行都有一Contract_StatusID列，從表中保存 FK Contract_Statuses- 表Contracts有更多具有此邏輯的列

事實是，顯式加載僅完全加載表的最后一行，其他行的列是隨機的null，即使集合.Include(s => s.Contract_Status)來自控制器代碼。設定了所有ID列，這些ID存在于相關表中，但未在Index頁面加載到該表中。

Detail頁面始終正確加載所有.Include()關系表，但不在Index頁面上。

我已經驗證了我的模型，它們看起來不錯，并且可以在網站的其他頁面中使用。

我缺少什么？已經為此瀏覽了 MSDN 和 EFCore 教程，但它不起作用。

public async Task<IActionResult> Index()
{
    var contract = await context.Contracts
        .Include(c => c.Employee)
            .ThenInclude(c => c.Gender)
        .Include(i => i.Business_Unit)
        .Include(i => i.Brand)
        .Include(i => i.Contract_Status)
        .Include(i => i.Statutory_Unit)
        .Include(i => i.Management_Market).ToListAsync();
    return View(contract);
}

編輯：添加我的 Index.cshtml

@model IEnumerable<MyProject.Models.Contract>    
<table >
        <thead>
            <tr>
                <th>
                    @Html.DisplayNameFor(model => model.Employee)
                </th>
                <th>
                    @Html.DisplayNameFor(model => model.Contract_Status.Contract_Status)
                </th>
                <th>
                    @Html.DisplayNameFor(model => model.Business_Unit.Business_Unit)
                </th>
                <th>
                    @Html.DisplayNameFor(model => model.Brand.Brand)
                </th>
                <th>
                    @Html.DisplayNameFor(model => model.Statutory_Unit.Statutory_Unit)
                </th>
                <th>
                    @Html.DisplayNameFor(model => model.Management_Market.Management_Market)
                </th>
                <th></th>
            </tr>
        </thead>
        <tbody>
            @foreach (var item in Model)
            {
            <tr>
                <td>
                    @Html.DisplayFor(modelItem => item.Employee.EmployeeID)
                </td>
                <td>
                    @Html.DisplayFor(modelItem => item.Contract_Status.Contract_Status)
                </td>
                <td>
                    @Html.DisplayFor(modelItem => item.Business_Unit.Business_Unit)
                </td>
                <td>
                    @Html.DisplayFor(modelItem => item.Brand.Brand)
                </td>
                <td>
                    @Html.DisplayFor(modelItem => item.Statutory_Unit.Statutory_Unit)
                </td>
                <td>
                    @Html.DisplayFor(modelItem => item.Management_Market.Management_Market)
                </td>
                <td>
                    <a asp-action="Edit" asp-route-id="@item.ContractID">Edit</a> |
                    <a asp-action="Details" asp-route-id="@item.ContractID">Details</a>
                </td>
            </tr>
            }
        </tbody>
    </table>

我的Contract模型與相關表的示例

    public class Contract
    {
        [Key]
        [Required]
        public Guid ContractID { get; set; }

        [Required]
        public string EmployeeID { get; set; }
        public Employee Employee { get; set; }

        [Required]
        public int Contract_StatusID { get; set; }
        public CONF_Contract_Status Contract_Status { get; set; }

        [Required]
        public int Business_UnitID { get; set; }
        public CONF_Business_Unit Business_Unit { get; set; }

        [Required]
        public int BrandID { get; set; }
        public CONF_Brand Brand { get; set; }

        [Required]
        public int Statutory_UnitID { get; set; }
        public CONF_Statutory_Unit Statutory_Unit { get; set; }


        [Required]
        public int Management_MarketID { get; set; }
        public CONF_Management_Market Management_Market { get; set; }
    }

public class CONF_Contract_Status
{
    [Key]
    public int CS_ID { get; set; }

    [Required]
    [Display(Name = "Status")]
    public string Contract_Status { get; set; }

    [Required]
    public bool Enabled { get; set; }

    public Contract Contract { get; set; }
}

Contract表的 資料庫截圖

和 CONF_Contract_Status

uj5u.com熱心網友回復：

我通常總是為索引視圖創建視圖模型，因為它通常需要幾個字串列，但它可以有很多列。如果您只需要一列，則無需從服務器獲取整個記錄

 public class ContractVieModel
    {
        public Guid ContractID { get; set; }

        public string EmployeeName { get; set; }
        public  string Contract_Status { get; set; }
        public string Business_Unit { get; set; }
        
      .... and so on
    }

動作，你不要顯式地使用 Include

public async Task<IActionResult> Index()
{
    var model = await context.Contracts
    .Select(i=> new ContractViewModel
     {
       Id=i.Id,
       EmployeeName=i.Employee.Name
      Contract_Status =i.Contract_Status.Contract_Status,
      Business_Unit = i.Business_Unit.Business_Unit,
      ... and so on 
      }).ToListAsync();

    return View(model);
}

看法

@model IEnumerable<ContractViewModel> 

......

試試看，如果它仍然不起作用，那么你將不得不使用左外連接來獲得一個視圖模型

標籤：asp.net核心 实体框架核心 .net-5

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