将数据从 ViewModel 传递到 View 和 PartialView 出现问题

Question

我正在构建一个非常简单的博客。对于我的博客，我需要两个模型：cmets 和消息。我知道要在您的视图中使用两个模型，您需要一个 ViewModel，但我遇到了很多困难。出于某种原因，我无法同时访问这两个模型，我的部分观点也是如此。现在我对 asp.net mvc 很陌生，知道这可能是一个愚蠢的错误，但我希望有人能告诉我我做错了什么，最重要的是为什么！

这是我的模型

namespace Portfolio.Models
{
    public class Messages
    {
        public int MessagesId { get; set; }
        [Required]
        public string Title { get; set; }
        [Required]
        public string Body { get; set; }
        public DateTime WhenCreated { get; set; }

        public Messages()
        {
            WhenCreated = DateTime.Now;
        }
    }
}

namespace Portfolio.Models
{
    public class Comments
    {
        public int CommentsId { get; set; }
        public string Comments_body { get; set; }
        public Messages MessagesId { get; set; }
        public DateTime WhenCreated { get; set; }

        public Comments()
        {
            WhenCreated = DateTime.Now;
        }
    }
}

这是我的 ViewModel

namespace Portfolio.ViewModels
{
    public class MessageViewModel
    {
        public IEnumerable<Messages> Messages { get; set; }
        public IEnumerable<Comments> Comments { get; set; }
    }
}

我的控制器

    namespace Portfolio.Controllers
{
    public class MessagesController : Controller
    {
        private ApplicationDbContext _context;

        public MessagesController()
        {
            _context = new ApplicationDbContext();
        }

        protected override void Dispose(bool disposing)
        {
            _context.Dispose();
        }
        public ActionResult Blog()
        {
            var messages = _context.messages.ToList();

            return View(_context.messages.OrderByDescending(Messages => 
            Messages.WhenCreated));
        }

        public ActionResult Comment()
        {
            var comment = _context.comments.ToList();

            return View(_context.comments.OrderByDescending(Comments => 
            Comments.WhenCreated));
        }
        public ActionResult Post()
        {
            return View();
        }


        //This binds the objects from the database to the values from the 
        view

        [ValidateInput(false)]
        [HttpPost]
        public ActionResult Create(FormCollection formValues)
        {
            try
            {
                Messages message = new Messages();
                message.Title = formValues["Title"];
                message.Body = formValues["editor"];

                Comments comment = new Comments();
                comment.Comments_body = formValues["editor" + 
                message.MessagesId];

                _context.comments.Add(comment);
                _context.SaveChanges();
                _context.messages.Add(message);
                _context.SaveChanges();

           }
            catch
            {
                return View();
            }
            return RedirectToAction("Blog");
       }
    }
}

这是我的观点

@model IEnumerable<Portfolio.ViewModels.MessageViewModel>

@{
    ViewBag.Title = "Blog";
    Layout = "~/Views/Shared/_Layout.cshtml";
 }
<link rel="stylesheet" type="text/css" href="~/Content/css/Blog.css" />
<script src="~/Scripts/ckeditor/ckeditor.js"></script>

<div class="jumbotron opacity_container">
    <div class="row">
        <div class="col-md-12">
            <h2>Latest Posts</h2>
            <div class="row">
                <div class="col-md-12">
                    @foreach (var messages in Model)
                    {
                        <div class="jumbotron opacity_container">
                            <div class="col-md-12">
                                <div class="panel panel-primary">
                                    <div class="panel-heading">
                                        @*Gets the title of the blog post*@
                                        <h2 class="panel-title">
                                        @messages.Title
                                        </h2>@messages.WhenCreated
                                   </div>
@*Gets the body of the blog post and decodes the html of the ckeditor*@

                                <div class="panel-body">
                 @Html.Raw(System.Web.HttpUtility.HtmlDecode(messages.Body))
                                </div>
                            </div>
                        </div>
 @*this button gets the id from the database of the 
 Message table this helps to prevent that all the comments from all blogs 
 gets shown and thus shows only the comments that belong to the blog in 
 question*@

                    <button class="btn btn primary"id="@messages.MessagesId"
                    onclick="ShowComments(this.id)">
                    Show Comments
                    </button>

@*this is the container where al the comments are placed in and where you 
can post comments. The comments are placed in the Comment partial view*@
                        <div class="hidden" id="Comm@(messages.MessagesId)">
                            @Html.Partial("_Comment", Model)

@*this button gets the id from the database of the Message table this helps 
to prevent that all the comments from all blogs gets hidden and thus
hides only the comments that belong to the blog in question*@
                        <button class="btn btn-primary" 
                        id="@messages.MessagesId" 
                        onclick="HideComments(this.id)">Hide Comments
                        </button>
                    </div>
                </div>
                }
            </div>
        </div>
    </div>
</div>

这是我的部分观点

@{
   ViewBag.Title = "Home Page";
}
<link rel="stylesheet" type="text/css" href="~/Content/css/Blog.css" />

<div class="row" id="CommentContainer">
    <div class="col-md-12">
        <h3>Post Comment</h3>
 @*The form to post comments*@
        @using (Html.BeginForm("Create", "Messages"))
            {
            <div class="form-group">
                <label>Comment</label>
                @Html.TextArea("editor1", htmlAttributes: new { name = 
               "editor1", id = "editor", rows = "10", cols = "180" })
            </div>
                <button type="submit" class="btn btn-primary" 
              id="PostButton">Post Comment</button>
            }

 @*CKEdito script*@
        <script>
             CKEDITOR.replace('editor1');
        </script>


        <div class="row">
            <div class="col-md-10">
@*Places al the comments and decodes the html from the ckeditor*@
                @foreach(var comments in Model)
                {
                    <div class="well" id="CommentBox">

@Html.Raw(System.Web.HttpUtility.HtmlDecode(comments.Comments_body))
                    </div>
                }
            </div>
        </div>
    </div>
</div>

此 PartialView 显示 cmets，而 View 显示博客消息。 所以我需要将数据从我的消息模型发送到我的视图，并且我需要在我的局部视图中从我的 cmets 模型发送和检索数据。

感谢您的帮助！

Answer 1

为了在您的视图中使用您的 ViewModel，您需要将它从您的控制器传递给您的视图。您当前正在传递一组消息：

public ActionResult Blog()
{
    var messages = _context.messages.ToList();

    // Your view is expecting a parameter of type MessageViewModel,
    // but you're passing it an object of type List<Messages>
    return View(_context.messages.OrderByDescending(Messages => Messages.WhenCreated));
}

如果您想使用 ViewModel，请尝试以下操作：

public ActionResult Blog()
{
    // Create a MessageViewModel and assign its properties...
    var viewModel = new MessageViewModel()
        {
           Messages = _context.messages.OrderByDescending(m => m.WhenCreated),
           Comments =  _context.comments
        };

    // Pass the MessageViewModel to your view.
    return View(viewModel);
}

您还需要更新您的视图：

@model Portfolio.ViewModels.MessageViewModel
...
@foreach (var messages in Model.Messages)
...
@Html.Partial("_Comment", Model.Comments)

你会想让你的局部视图接受一个参数 IEnumerable<Comments> 的型号：

@model IEnumerable<Portfolio.Models.Comments>

请注意，此解决方案当前正在从 _context 获取 所有 消息和 所有 cmets 并将它们传递给视图。您可能想要过滤它们（仅传递附加到特定消息的 cmets 等）。