将数据从视图传递到控制器并从控制器传回视图

Question

我在 ASP.NET 中编写一个简单的应用程序时遇到问题。 我的想法是从该表单传递数据以在我的控制器中创建电影，然后我希望此控制器（AddMovie）将此电影发送到我的电影列表，并且我希望它显示在视图中。 我尝试了一些方法，但都没有奏效。我该怎么做？

查看：

@model IEnumerable<Movie>
@{
    // ViewData["Title"] = "MovieView";

    ViewBag.Title = "Welcome to My Page";

}
<h1>MoviesView</h1>

@foreach (var item in Model)
{
<div class="text-center">
    <p>Id:item.Id </p>
    <p>Name:item.Name</p>
    <p>Author: item.Author</p>
   
</div>
<br />
}
<br />
<form asp-controller="MoviesController" method="post">
    Id: <input type="text" name="movieId" /><br />
    Name: <input type="text" name="movieName" /><br />
    Author: <input type="text" name="movieAuthor" />
    <input type="submit" value="Submit" formaction="AddMovie" /> &nbsp;&nbsp;&nbsp;

</form>
<p>@ViewBag.Result</p>

控制器：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using WebMVCAPP_L.Models;

namespace WebMVCAPP_L.Controllers
{
    public class MoviesController : Controller
    {
        List<Movie> movieList = new List<Movie>();

        public IActionResult Index()
        {
            return View(movieList);
        }
        [HttpPost]
        public IActionResult AddMovie()
        {
            int id = Convert.ToInt32(HttpContext.Request.Form["movieId"].ToString());
            string name = HttpContext.Request.Form["movieName"].ToString();
            string author = HttpContext.Request.Form["movieAuthor"].ToString();

            Movie movie = new Movie(id,name,author);
            movieList.Add(movie);
            return View("Index");
        }
    }
}

Answer 1

首先，您需要某种方式来持久化您的List<Movie>()。 HTTP，因此 MVC，是无状态的。理想情况下，您将使用数据库，但您可以使用 Session 进行测试：

List<Movie> movieList
{
    get
    {
        if (Session["movieList"] == null)
        {
            Session["movieList"] = new List<Movie>();
        }
        return Session["movieList"] as List<Movie>;
    }
}

您还需要将asp-action 添加到您的表单中，以回复您的AddMovie 方法：

<form asp-controller="MoviesController" asp-action="AddMovie" method="post">

然后，更改您的方法签名：

public IActionResult AddMovie(int id, string name, string author)

MVC 框架会自动将表单字段绑定到同名的参数。

最后，返回一个 HTTP 重定向而不是视图本身：

[HttpPost]
public IActionResult AddMovie()
{
    Movie movie = new Movie(id, name, author);
    movieList.Add(movie);
    return RedirectToAction("Index");
}

然后，浏览器将对（持久的）电影列表的Index 方法执行 HTTP GET。

Answer 2

它向我展示了类似An unhandled exception occurred while processing the request. InvalidOperationException: The 'Microsoft.AspNetCore.Mvc.ViewFeatures.Infrastructure.DefaultTempDataSerializer' cannot serialize an object of type 'System.Collections.Generic.List`1[WebMVCAPP_L.Models.Movie]'. Microsoft.AspNetCore.Mvc.ViewFeatures.Infrastructure.DefaultTempDataSerializer.Serialize(IDictionary<string, object> values)

Stack Query Cookies Headers Routing 

InvalidOperationException: The 'Microsoft.AspNetCore.Mvc.ViewFeatures.Infrastructure.DefaultTempDataSerializer' cannot serialize an object of type 'System.Collections.Generic.List`1[WebMVCAPP_L.Models.Movie]'.
    Microsoft.AspNetCore.Mvc.ViewFeatures.Infrastructure.DefaultTempDataSerializer.Serialize(IDictionary<string, object> values)
    Microsoft.AspNetCore.Mvc.ViewFeatures.CookieTempDataProvider.SaveTempData(HttpContext context, IDictionary<string, object> values)
    Microsoft.AspNetCore.Mvc.ViewFeatures.TempDataDictionary.Save()
    Microsoft.AspNetCore.Mvc.ViewFeatures.Filters.SaveTempDataFilter.SaveTempData(IActionResult result, ITempDataDictionaryFactory factory, IList<IFilterMetadata> filters, HttpContext httpContext)
    Microsoft.AspNetCore.Mvc.ViewFeatures.Filters.SaveTempDataFilter.OnResultExecuted(ResultExecutedContext context)
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext<TFilter, TFilterAsync>(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeResultFilters()
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()
    Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
    Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
    Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
    Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)```

Answer 3

当您从一个操作路由到另一个操作时，您需要使用临时数据。

namespace WebMVCAPP_L.Controllers
{
    public class MoviesController : Controller
    {
        List<Movie> movieList = new List<Movie>();

        public IActionResult Index()
        {
            if(TempData["myData"]!=null){

                movieList = JsonConvert.DeserializeObject<List<Movie>>((String)TempData["myData"]);
             }
            return View(movieList);
        }
        [HttpPost]
        public IActionResult AddMovie()
        {
            int id = Convert.ToInt32(HttpContext.Request.Form["movieId"].ToString());
            string name = HttpContext.Request.Form["movieName"].ToString();
            string author = HttpContext.Request.Form["movieAuthor"].ToString();

            Movie movie = new Movie(id,name,author);
            movieList.Add(movie);
             String str = JsonConvert.SerializeObject(movieList)
             TempData["myData"] = str ;
            return View("Index");
        }
    }
}

<form asp-action="AddMovie" asp-controller="Movies">

    <input type="submit" />
</form>