其他输入验证干扰了应该允许 null 的输入

Question

大家好，我正在尝试使用带有代码优先数据库的 asp.net mvc 创建一个应用程序，该数据库允许用户创建包含任意数量图像的博客文章。只要我的头部、身体和图像字段已满，或者如果我对头部和身体进行验证，该应用程序就可以完美运行。问题是如果我在头部和身体上进行验证，程序会因以下验证错误而崩溃：

DbEntityValidationException Crud.dll 中出现“System.Data.Entity.Validation.DbEntityValidationException”类型的异常，但未在用户代码中处理

附加信息：一个或多个实体的验证失败。有关更多详细信息，请参阅“EntityValidationErrors”属性。验证错误是：标题是必需的；正文是必需的

感谢您对此问题的帮助。

查看

@model Crud.Models.PostModel
@{
    ViewBag.Title = "Create";
}
<h2>Create</h2>
@using (Html.BeginForm("Edit", "Home", null, FormMethod.Post, new { enctype = "multipart/form-data" }))
{
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)
    <fieldset>
        <div class="editor-field">
            @Html.LabelFor(model => model.Heading)
            @Html.TextBoxFor(model => model.Heading)
            @Html.ValidationMessageFor(model => model.Heading)
        </div>
        <div>
            @Html.LabelFor(model => model.PostBody)
            @Html.TextBoxFor(model => model.PostBody)
            @Html.ValidationMessageFor(model => model.PostBody)
        </div>
        <div class="editor-label">
            @*Temporary way to upload*@
            @Html.LabelFor(model => model.ImagePath)
            @Html.TextBoxFor(model => model.ImagePath, new { type = "file", multiple = "multiple", NAME = "files" })
        </div>
        <div class="editor-label">
            @*Future Upload links*@
            @*@Html.LabelFor(model => model.Images)
            @Html.TextBoxFor(model => model.Images, new { type = "file", multiple = "multiple" })
            @Html.ValidationMessageFor(model => model.Images)*@
        </div>

        <p><input type="submit" value="Create" /></p>
    </fieldset>
}
<div>
    @Html.ActionLink("Back to List", "Index")
</div>

存储库

public void Save(PostModel Post)
{
    try
    {
        if (Post.PostID == 0)
        {
            context.Posts.Add(Post);
        }
        else
        {
            PostModel dbEntry = context.Posts.Find(Post.PostID);
            if (dbEntry != null)
            {
                dbEntry.Heading = Post.Heading;
                dbEntry.PostBody = Post.PostBody;

            }
        }
        context.SaveChanges();

    }
    catch (DbEntityValidationException ex)
    {
        // Retrieve the error messages as a list of strings.
        var errorMessages = ex.EntityValidationErrors
                .SelectMany(x => x.ValidationErrors)
                .Select(x => x.ErrorMessage);

        // Join the list to a single string.
        var fullErrorMessage = string.Join("; ", errorMessages);

        // Combine the original exception message with the new one.
        var exceptionMessage = string.Concat(ex.Message, " The validation errors are: ", fullErrorMessage);

        // Throw a new DbEntityValidationException with the improved exception message.
        throw new DbEntityValidationException(exceptionMessage, ex.EntityValidationErrors);
    }
}

型号

  public partial class PostModel
    {
        [Key]
        [HiddenInput(DisplayValue = false)]
        public int PostID { get; set; }
        [Required(ErrorMessage = "Heading is Required")]
        [Display(Name = "Heading")]
        public string Heading { get; set; }
        [Required(ErrorMessage = "Body is Required")]
        [DataType(DataType.MultilineText)]
        [Display(Name = "Body")]
        public string PostBody { get; set; }
        public string ImageDisplayName { get; set; }
        public string ImagePath { get; set; } //Temporarly here until I can get the ImageModel Method Working
        //public virtual ICollection<ImageModel> Images { get; set; }
    }

控制器

  public ViewResult Create()
    {
        return View("Edit", new PostModel());

    }

public ViewResult Edit(int PostID)
{
    PostModel editedItem = repository.Posts
    .FirstOrDefault(p => p.PostID == PostID);
    return View(editedItem);
}
[HttpPost]
public ActionResult Edit(PostModel Post, IEnumerable<HttpPostedFileBase> files)
{
    if (ModelState.IsValid)
    {
        foreach (var file in files)
        {
            PostModel post = new PostModel();
            if (file != null && file.ContentLength > 0)
            {
                string displayName = file.FileName;
                string fileExtension = Path.GetExtension(displayName);
                string fileName = string.Format("{0}.{1}", Guid.NewGuid(), fileExtension);
                string path = Path.Combine(Server.MapPath("~/Img/"), fileName);
                file.SaveAs(path);
                post.ImageDisplayName = displayName;
                post.ImagePath = fileName;
                post.PostBody = Post.PostBody;
                post.Heading = Post.Heading;
            }
            repository.Save(post);

        }
    }
    return RedirectToAction("display");
}

Answer 1

如果字段实际上不是必需的，为什么要添加 [Required] 属性？请参阅此处了解如何处理字符串的必需属性 - Allow empty strings for fields marked with PhoneAttribute or UrlAttribute