c# asp.net core mvc 将数据从视图传递到控制器并从控制器返回到视图

Question

I have a problem writing a simple app in asp.net. My idea is to pass data from that form to create a movie in my controller and then I want this controller (AddMovie) to sen this movie to my movieList and I want this to be shown in the view. I tried some ways, but none worked. How can I do that?

View:

@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>

Controller:

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

When you routing from one action to another action then you need to use tempdata.

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>

Answer 2

Before anything else, you need some way of persisting your List<Movie>() . HTTP, and therefore MVC, is stateless. Ideally you would be using a database, but you could use Session for testing purposes:

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

Yo also need to add asp-action to your form to post back to your AddMovie method:

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

Then, change your method signature:

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

The MVC framework will automatically bind form fields to arguments of the same name.

Finally, return a HTTP redirect rather than the view itself:

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

The browser will then perform a HTTP GET to your Index method for the (persisted) movie list.

Answer 3

It shows me something like this 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) 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)```