Question

我有一个mvc4应用程序。用户可以在每个项目上创建新项目并添加注释。（我无法解决评论添加部分）

我有两个型号 1.Comment

public partial class Comment
    {
        public int CommentID { get; set; }
        public string Title { get; set; }
        public int ProjectID { get; set; }
        public string Rating { get; set; }

        public virtual Project Project { get; set; }
    }

2，项目

public partial class Project
    {
        public Project()
        {
            this.Comments = new HashSet<Comment>();
        }

        public int ProjectID { get; set; }
        public string Name { get; set; }
        public string Goal { get; set; }

        public virtual ICollection<Comment> Comments { get; set; }
    }

现在我想在项目控制器索引页面上显示以下操作链接：编辑|细节|删除|添加评论（编辑，详细信息和删除功能工作正常，但无法创建注释）

这是我的项目负责人：

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using ProjectCreation.Models;

namespace ProjectCreation.Controllers
{
    public class ProjectController : Controller
    {
        private ProjectCreationEntities db = new ProjectCreationEntities();

        //
        // GET: /Project/

        public ActionResult Index()
        {
            return View(db.Projects.ToList());


        }

        //
        // GET: /Project/Details/5

        public ActionResult Details(int id = 0)
        {
            Project project = db.Projects.Find(id);
            if (project == null)
            {
                return HttpNotFound();
            }
            return View(project);
        }


        //
        // GET: /Project/Create

        public ActionResult Create()
        {
            return View();
        }

        //
        // POST: /Project/Create

        [HttpPost]
        public ActionResult Create(Project project)
        {
            if (ModelState.IsValid)
            {
                db.Projects.Add(project);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            return View(project);
        }

        //
        // GET: /Project/Edit/5

        public ActionResult Edit(int id = 0)
        {
            Project project = db.Projects.Find(id);
            if (project == null)
            {
                return HttpNotFound();
            }
            return View(project);
        }

        //
        // POST: /Project/Edit/5

        [HttpPost]
        public ActionResult Edit(Project project)
        {
            if (ModelState.IsValid)
            {
                db.Entry(project).State = EntityState.Modified;
                db.SaveChanges();
                return RedirectToAction("Index");
            }
            return View(project);
        }

        //
        // GET: /Project/Delete/5

        public ActionResult Delete(int id = 0)
        {
            Project project = db.Projects.Find(id);
            if (project == null)
            {
                return HttpNotFound();
            }
            return View(project);
        }

        //
        // POST: /Project/Delete/5

        [HttpPost, ActionName("Delete")]
        public ActionResult DeleteConfirmed(int id)
        {
            Project project = db.Projects.Find(id);
            db.Projects.Remove(project);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        protected override void Dispose(bool disposing)
        {
            db.Dispose();
            base.Dispose(disposing);
        }

      **  public ActionResult Comment(int id = 0)
        {
            Comment comment = db.Comments.Find(id);

            if (comment == null)
            {
                return HttpNotFound();
            }
            return View(comment);
        }

        [HttpPost]
        public ActionResult Comment(Comment comment)
        {
            if (ModelState.IsValid)
            {
                db.Comments.Add(comment);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            return View(comment);
        } **
    }
}

我不知道如何点击“添加评论链接”创建评论。其余的项目控制器工作正常。这是我的评论控制器操作的视图页面：

@model ProjectCreation.Models.Comment

@{
    ViewBag.Title = "Comment";
}

<h2>Comment</h2>

@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>Comment</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.Title)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Title)
            @Html.ValidationMessageFor(model => model.Title)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.ProjectID)
        </div>
        <div class="editor-label">
            @Html.EditorFor(model => model.ProjectID)

        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Rating)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Rating)
            @Html.ValidationMessageFor(model => model.Rating)
        </div>

        <p>
            <input type="submit" value="Create" />
        </p>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

有人可以指导我。我准确地传递了项目ID。我似乎无法创建新的评论。视图页面已打开但没有更新。它甚至显示项目ID而不是标签的下拉。

Answer 1

您的控制器发送anoter模型类型，然后发送视图'想要'。类型必须相同

更改

@model IEnumerable<ProjectCreation.ViewModels.ProjectCreation>

到

@model List<ProjectCreation.ViewModels.ProjectCreation>

Answer 2

问题在于：

[HttpPost]
public ActionResult Comment(Comment comment)
{
    if (ModelState.IsValid)
    {
        db.Comments.Add(comment);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    return View(comment);
}

您忘记加载数据库并添加Create函数（）。它应该是这样的：

[HttpPost]
public ActionResult Comment(Comment comment)
{
    if (ModelState.IsValid)
    {
        using (var db = new ProjectCreationEntities())
        {
            var user = db.Comments.Create();
            user.CommentId = comment.CommentID;
            user.Title = comment.Title;
            user.ProjectId = comment.ProjectId;
            user.Rating = comment.Rating;
            db.Comments.Add(user);
            db.SaveChanges();
        }
        return RedirectToAction("Index");
    }

    return View(comment);
}

Answer 3

您的观点会显示ProjectCreation类型的模型并且在ActionResult你正在通过Project模型。

您必须在ActionResult中返回List<ProjectCreation>

UPDATE：

如果您希望labelfor helper显示您想要的名称，则viewModel中的

@Html.LabelFor(model => model.ProjectID)使用[DisplayName（“PropertyName”）]属性

public class Comment
{
[DisplayName("PropertyName")]
public int ProjectId{get;set;}
}

要创建您的评论，您需要使用HttpGet请求的ActionResult

[HttpGet]
public ActionResult Comment()
{
     var model = new Comment();
     return View(model);
}

只有这样你才能发布它你的ActionResult for Post：

   [HttpPost]
    public ActionResult Comment(Comment comment)
        {
            if (ModelState.IsValid)
            {
                db.Comments.Add(comment);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            return View(comment);
        }

Answer 4

也许我误解了你的代码，但在我看来，你只有代码来编辑和保存评论，而不是创建新的代码。

此代码段来自您自己的代码。在第一个函数中，您只允许显示注释（如果它们已存在）。但是你如何展示一个未创造的形式呢？在我看来，当你尝试创建一个新的评论（并且还没有id）时，你最终会得到HttpNotFound（）的回复。

    public ActionResult Comment(int id = 0)
    {
        Comment comment = db.Comments.Find(id);

        if (comment == null)
        {
            return HttpNotFound();
        }
        return View(comment);
    }

    [HttpPost]
    public ActionResult Comment(Comment comment)
    {
        if (ModelState.IsValid)
        {
            db.Comments.Add(comment);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        return View(comment);
    }

我会尝试添加一个新动作来创建新评论，可能是这样的：

    public ActionResult CreateComment()
    {
        return View("Comment");
    }

在mvc4中查看模型显示错误

4 个答案:

UPDATE：