为什么我的输入类型=“文件”总是返回 null 到 ASP.NET MVC 和实体框架中的视图模型

Question

我有一个使用 post 方法将一些信息发送到视图 model 的页面，它返回除设置为 null 的文件之外的所有值，如此屏幕截图所示：

图像在视图 model 中显示文件值为 null

我试图将byte[]设置为某个已知长度，但这也无济于事。

这是我认为问题所在的代码部分

<div>
    <form asp-controller="ProfilePage" asp-action="UploadProfilePicture" method="post" enctype="multipart/form-data">
                <input asp-for="EmployeeNumber" type="hidden"  />
                <input asp-for="FirstName" type="hidden"  />
                <input asp-for="LastName" type="hidden"  />
                <input asp-for="TeamID" type="hidden"  />
                <input asp-for="Role" type="hidden"  />
                <input asp-for="SuggestionCount" type="hidden" onchange="fileCheck(this);" />
                <input asp-for="ProfilePicture" type="file" onchange="filecheck(this)" />
                <input type="Submit" value="Submit" />
    </form>
</div>

如果您可能想查看它们，下面是完整的代码页

@model NordicDoorSuggestionSystem.Models.Employees.ProfileViewModel

@{
    ViewBag.Title = "Profil § NSS";
    Layout = "~/Views/Shared/_ProfileLayout.cshtml";
}

<center>
    <div id="cardContainer" class="cardContainer">
        <div class="card">
            <div class="cardPicture">
                <i class="fa fa-user" style="font-size:75px; color: grey;"></i>
                <button class="profileUpload" type="button" name="button">Nytt bilde</button>
                <@*form asp-controller="ProfilePage" asp-action="UploadProfilePicture" method="get">
                    <input type="image" name="NewProfilePicture" id="NewImageData" onchange="fileCheck(this);" />
                </form>*@
            </div>
            <div class="cardHeader">
                <label>@Html.DisplayFor(model => model.FirstName) @Html.DisplayFor(model => model.LastName)</label>
            </div>
            <div class="cardProfileInfo">
                <p>Ansatt nr: <label>@Html.DisplayFor(model => model.EmployeeNumber)</label> </p>
                <p>Rolle: <label>@Html.DisplayFor(model => model.Role)</label> </p>
                <p>Team: <label>@Html.DisplayFor(model => model.TeamName)</label> </p>
            </div>
            <div>
                <form asp-controller="ProfilePage" asp-action="UploadProfilePicture" method="post" enctype="multipart/form-data">
                    <input asp-for="EmployeeNumber" type="hidden"  />
                    <input asp-for="FirstName" type="hidden"  />
                    <input asp-for="LastName" type="hidden"  />
                    <input asp-for="TeamID" type="hidden"  />
                    <input asp-for="Role" type="hidden"  />
                    <input asp-for="SuggestionCount" type="hidden" onchange="fileCheck(this);" />
                    <input asp-for="ProfilePicture" type="file" onchange="filecheck(this)" />
                    <input type="Submit" value="Submit" />
                </form>
 
            </div>
            <div class="showMyStats">
                <center>
                    <div class="stats">
                          <div class="present">
                            <div class="lid">
                                <span></span>
                            </div>
                        <div class="promo">
                            <p>DU HAR</p>
                            <h2>@Html.DisplayFor(model => model.SuggestionCount) Forslag!</h2>
                        </div>
                        <div class="box">
                            <span></span>
                            <span></span>
                        </div>
                    </div>
                    </div>
                </center>
            </div>
        </div>
    </div>
</center>

---

public class ProfilePageController : Controller
{
    private readonly UserManager<User> _userManager;
    private readonly DataContext _context;
    private readonly IEmployeeRepository _employeeRepository;

    public ProfilePageController(UserManager<User> userManager, DataContext context, IEmployeeRepository employeeRepository)
    {
        _userManager = userManager;
        _context = context;
        _employeeRepository = employeeRepository;
    }

    // GET: /<controller>/
    public async Task<IActionResult> Index()
    {
        var currentUser = await _userManager.GetUserAsync(HttpContext.User);
        ProfileViewModel vm = new ProfileViewModel();
        if (currentUser == null)
        {
            return NotFound();
        }
        var employee = _employeeRepository.GetEmployeeByNumber(currentUser.EmployeeNumber);
        vm.EmployeeNumber = currentUser.EmployeeNumber;
        vm.FirstName = currentUser.FirstName;
        vm.LastName = currentUser.LastName;
        vm.Role = currentUser.Role;
        vm.TeamID = employee.TeamID;
        var teamname = _context.Team.Where(e => e.TeamID.Equals(employee.TeamID)).Select(e => e.TeamName).FirstOrDefault();
        vm.TeamName = teamname;
        vm.SuggestionCount = employee.SuggestionCount;
        //vm.ProfilePicture = employee.ProfilePicture; 
        return View(vm);
    }

    // GET: /<controller>/
    public IActionResult Statistic()
    {
        return View();
    }

    //byte[] picture ???
    [HttpPost]
    public async Task<IActionResult> UploadProfilePicture(ProfileViewModel profilevm)
    {
        //byte[] ImageToByteArray(System.Drawing.Image imageIn)
        //{
        //    using (var ms = new MemoryStream())
        //    {
        //        imageIn.Save(ms, imageIn.RawFormat);
        //        return ms.ToArray();
        //    }
        //}

        //var Imgtemp = new byte[16777215];
        //Imgtemp[16777215] = ImageToByteArray(profilevm.ProfilePicture);

        var employee = new Employee
        {
            EmployeeNumber = profilevm.EmployeeNumber,
            FirstName = profilevm.FirstName,
            LastName = profilevm.LastName,
            Role = profilevm.Role,
            TeamID = profilevm.TeamID,
            ProfilePicture = profilevm.ProfilePicture,
            SuggestionCount = profilevm.SuggestionCount,
        };
        _employeeRepository.Update(employee);

        return RedirectToAction("Index");
    }
}

namespace NordicDoorSuggestionSystem.Models.Employees
{
    public class ProfileViewModel
    {
        public int EmployeeNumber { get; set; }
        public string? FirstName { get; set; }
        public string? LastName { get; set; }
        public string? AccountState { get; set; }
        public string Role { get; set; }
        public byte[]? ProfilePicture { get; set; }
        public int? TeamID { get; set; }
        public int? SuggestionCount { get; set; }
        public string? TeamName { get; set; }
    }
}

该代码用于我的第 3 学期 uni 项目

这是存储图片的员工实体部分的截图

图片显示了将存储图像的长 blob

Answer 1

input type="file" 总是返回 null

尝试使用IFormFile ，更改为您的 model

public IFormFile ProfilePicture { get; set; }

并采用以下形式：

 <input asp-for="ProfilePicture" type="file" onchange="filecheck(this)" />

结果：