c# - Visual Studio 中的错误：无法将类型“string”隐式转换为“int”

Question

这是作业，一个使用 C# 在 Visual Studio 中的 ASP.NET MVC 应用程序。当我运行它时，错误提示“无法将类型'string'隐式转换为'int'”，指的是以下行：Manufacturer = collection["Manufacturer"], Gears = collection["Gears"], Frame = collection[ "Frame"] 并且在 Gears = collection["Gears"] 下有一条波浪线。

using MvcApplication3.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace MvcApplication3.Controllers
{
    public class BikeController : Controller
    {
        //
        // GET: /Bike/

        List<Bike> bikes;


        public BikeController()
        {
            if (bikes == null)
            {
                bikes = new List<Bike> {
                new Bike(),
                new Bike { Manufacturer = "Nishiki", Gears = 5, Frame = "Road" }
            };
            }
        }

        public ActionResult Index()
        {
            return View(this.bikes);
        }

        private ActionResult View(Func<object> func)
        {
            throw new NotImplementedException();
        }

        //
        // GET: /Bike/Details/5

        public ActionResult Details(int id)
        {
            var currentBikes = bikes[id];
            return View(currentBikes);

        }

        //
        // GET: /Bike/Create

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

        //
        // POST: /Bike/Create

        [HttpPost]
        public ActionResult Create(FormCollection collection)
        {   
            Bike b = new Bike
            { 
                Manufacturer = collection["Manufacturer"], Gears = collection["Gears"], Frame = collection["Frame"]
            };
            bikes.Add(b);
            try
            {
                return RedirectToAction("Index");
            }
            catch
            {
                return View();
            }
        }

        //
        // GET: /Bike/Edit/5

        public ActionResult Edit(int id)
        {
            return View(bikes.Where(b => b.BikeID == id).First());
        }

        //
        // POST: /Bike/Edit/5

        [HttpPost]
        public ActionResult Edit(int id, FormCollection collection)
        {
            try
            {
                // TODO: Add update logic here

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

        //
        // GET: /Bike/Delete/5

        public ActionResult Delete(int id)
        {
            return View();
        }

        //
        // POST: /Bike/Delete/5

        [HttpPost]
        public ActionResult Delete(int id, FormCollection collection)
        {
            try
            {
                // TODO: Add delete logic here

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

        public int bike { get; set; }
    }
}

Answer 1

您需要将字符串显式转换为 int。

尝试以下行

  Manufacturer = collection["Manufacturer"], Gears = int.Parse(collection["Gears"]), Frame = collection["Frame"]