C# 表单未将数据保存到模型

我使用MVC来建立一个博客。我想要的是将post注释保存到数据库中相应的位置，但它不起作用

我的帖子模式如下：

public class Post
{
    [Key]
    public int PostId { get; set; }
    public string Title { get; set; }
    public DateTime CreatedDate{get;set;}
    public DateTime UpdateDate { get; set; }
    public string Body { get; set; }
    public ICollection<Comment> Comments { get; set;}
    public ICollection<Tag> Tags { get; set; } 

}

   public class Comment
    {

        [Key]
        public int CommentId { get; set; }
        public int PostId { get; set; }
        [ForeignKey("PostId")]
        public virtual Post Post{get; set;}
        public string CommentCreateDate { get; set; }
        public string CommentUpdateDate { get; set; }
        public string CommeterName { get; set; }
        public string EmailAddress { get; set; }
        public string CommentText { get; set; }
        public bool Approved { get; set; }

    }

 @using (Html.BeginForm(new {id = Model.CommentId}))
{
    <fieldset>

        <legend>Enter Comment</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.CommeterName)
        </div>
        <div class="editor-field">
            @Html.TextBoxFor(model => model.CommeterName)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.EmailAddress)
        </div>
        <div class="editor-field">
            @Html.TextBoxFor(model => model.EmailAddress)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.CommentText)
        </div>
        <div class="editor-field">
            @Html.TextAreaFor(model => model.CommentText)
        </div>
        <p>
            <input type="submit" value="Create comment" />
        </p>

    </fieldset>

}

我有以下行动方法：

[HttpGet]
    public ActionResult CreateComment()
    {
        return View();
    }

    [HttpPost]
    [ValidateInput(false)]
    public ActionResult CreateComment(int id, string name, string email, string txt, bool aproved = false)
    {

        Post post = GetPost(id);
        Comment comment = new Comment();
        comment.Post = post;
        comment.CommentCreateDate = DateTime.Now.ToString();
        comment.CommeterName = name;
        comment.EmailAddress = email;
        comment.CommentText = txt;
        comment.Approved = aproved;
        db.Comments.Add(comment);
        db.SaveChanges();

        m_commentList.Add(comment);



        return RedirectToAction("CreateComment", new { id = id });

    }

在我看来，我正在尝试：

@model Blog.Models.Comment

@{
    ViewBag.Title = "CreateComment";
}

<h2>Create a Comment</h2>


    @using (Html.BeginForm())
    {
        <fieldset>

            <legend>Enter Comment</legend>

            <div class="editor-label">
                @Html.LabelFor(model => model.CommeterName)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(model => model.CommeterName)
            </div>
            <div class="editor-label">
                @Html.LabelFor(model => model.EmailAddress)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(model => model.EmailAddress)
            </div>
            <div class="editor-label">
                @Html.LabelFor(model => model.CommentText)
            </div>
            <div class="editor-field">
                @Html.TextAreaFor(model => model.CommentText)
            </div>
            <p>
                <input type="submit" value="Create comment" />
            </p>

        </fieldset>

    }

为什么会这样？有人能帮忙吗

---

谢谢你

你的行动签名应该是：

public ActionResult CreateComment(Comment model)

为表单字段生成的名称将绑定回同一模型类的属性。例如，框架无法知道

CommenterName

属性是否应该与操作的

name

参数匹配

您的第二个示例没有什么意义-您试图写出ID，但从未设置ID。事实上，您甚至没有将

注释

与表单一起传递给视图，这就是为什么会出现

NullReferenceException

：

[HttpGet]
public ActionResult CreateComment()
{
    return View();
}

此外，您还应该注意向模型和操作公开哪些字段。例如，用户只需通过浏览器的开发控制台添加以下标记，就可以轻松地强制批准其评论：

<input type="hidden" name="approved" value="true" />

然后将其映射到您的操作中的

注释

：

[HttpPost]
public ActionResult CreateComment(CommentViewModel model)
{
    var comment = new Comment();
    comment.CommenterName = model.Name;
    // etc...
}

---

这会阻止用户设置诸如

Approved

和

CreatedDate

之类的内容，不管您需要什么-我只是想为您演示一种更好的模型绑定方法。剩下的就看你了。谢谢你的帮助！！！但是仍然有必要像这样在签名中传递id：public ActionResult CreateComment（int？id，CommentViewModel model）没问题-请按照我回答的第二部分使用适当的视图模型（如果您还没有）。

public class CreateCommentViewModel
{
    public string Name { get; set; }
    public string Email { get; set; }
    public string Text { get; set; }
}

[HttpPost]
public ActionResult CreateComment(CommentViewModel model)
{
    var comment = new Comment();
    comment.CommenterName = model.Name;
    // etc...
}