嗨，人们是MVC3的新手和学习，我想知道是否有可能允许用户在我的网站上添加游戏时检查游戏是否已经输入。我想要这个功能，所以我网站上的任何玩家都无法对同一个游戏进行全面评论。这个原因我有一个页面，用户可以在这个页面上玩游戏。所以这就是为什么我想要在添加新游戏时检查数据库的方法，如果游戏存在的话。
我的控制器如下：
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Linq;
using PagedList;
using System.Web;
using System.Web.Mvc;
using System.IO;
using Test.Models;
namespace Test.Controllers
{
public class GameController : Controller
{
private gamezoneDBEntities db = new gamezoneDBEntities();
//
// GET: /Game/
public ViewResult Index(string Ordering, string WordFilter, string DisplaySearchResults, int? CounterForPage)
{
{
var Info = db.tblGames.Include(x => x.tblConsole);
}
var Games = from b in db.tblGames
.Where(U => U.UserName == User.Identity.Name)
select b;
switch (Ordering)
{
case "HeadlineName":
Games = Games.OrderBy(b => b.GameName);
break;
case "DatePosted":
Games = Games.OrderBy(b => b.ReleaseYear);
break;
case "DiscriptionDate":
Games = Games.OrderBy(b => b.ReleaseYear);
break;
default:
Games = Games.OrderByDescending(b => b.ReleaseYear);
break;
}
int pageSize = 3;
int pageNumber = (CounterForPage ?? 1);
var PageNumberResults = Games.ToPagedList(pageNumber, pageSize);
ViewBag.PageNumberResults = Games.Count();
if (PageNumberResults.Any())
{
return View(PageNumberResults);
}
return View("Error");
}
[HttpPost]
public ActionResult Create(tblGame tblgame,
HttpPostedFileBase image1,
HttpPostedFileBase image2)
{
try
{
if (ModelState.IsValid)
{
if (image1 != null)
{
string image = image1.FileName;
tblgame.Image = image;
var image1Path = Path.Combine(Server.MapPath("~/Content/UploadImages"), image);
image1.SaveAs(image1Path);
}
if (image2 != null)
{
string Image2 = image2.FileName;
tblgame.Image2 = Image2;
var image2Path = Path.Combine(Server.MapPath("~/Content/UploadImages"), Image2);
image2.SaveAs(image2Path);
}
db.tblGames.Add(tblgame);
db.SaveChanges();
return RedirectToAction("Index");
}
ViewBag.ConsoleNameIDFK = new SelectList(db.tblConsoles, "ConsoleName", "ConsoleName", tblgame.ConsoleNameIDFK);
return View(tblgame);
}
catch
{
return View("Upload_Image_Failed");
}
}
//
// GET: /Game/Create
public ActionResult Create()
{
ViewBag.ConsoleNameIDFK = new SelectList(db.tblConsoles, "ConsoleName", "ConsoleName");
return View(new tblGame { UserName = @User.Identity.Name });
}
public ViewResult Details(int id)
{
tblGame tblgame = db.tblGames.Find(id);
return View(tblgame);
}
//
// GET: /Game/Edit/5
public ActionResult Edit(int id)
{
tblGame tblgame = db.tblGames.Single(i => i.GameID == id);
ViewBag.ConsoleNameIDFK = tblgame.ConsoleNameIDFK;
return View(tblgame);
}
[HttpPost]
public ActionResult Edit(tblGame tblgame, HttpPostedFileBase Image, int id,
HttpPostedFileBase image2)
{
if (ModelState.IsValid)
{
if (Image != null)
{
string image = Image.FileName;
tblgame.Image = image;
var image1Path = Path.Combine(Server.MapPath("~/Content/UploadImages"), image);
Image.SaveAs(image1Path);
}
if (image2 != null)
{
string Image2 = image2.FileName;
tblgame.Image2 = Image2;
var image2Path = Path.Combine(Server.MapPath("~/Content/UploadImages"), Image2);
image2.SaveAs(image2Path);
}
db.tblGames.Attach(tblgame);
db.Entry(tblgame).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Edit");
}
ViewBag.ConsoleNameIDFK = new SelectList(db.tblConsoles, "ConsoleName", "ConsoleName", tblgame.ConsoleNameIDFK);
return View(tblgame);
}
//
// GET: /Game/Delete/5
public ActionResult Delete(int id)
{
tblGame tblgame = db.tblGames.Find(id);
return View(tblgame);
}
//
// POST: /Game/Delete/5
[HttpPost, ActionName("Delete")]
public ActionResult DeleteConfirmed(int id)
{
try
{
tblGame tblgame = db.tblGames.Find(id);
db.tblGames.Remove(tblgame);
db.SaveChanges();
return RedirectToAction("Index");
}
catch
{
return View("Error");
}
}
protected override void Dispose(bool disposing)
{
db.Dispose();
base.Dispose(disposing);
}
}
}
我一直在努力寻找游戏allreday是否存在，因为我拥有使用户独一无二的代码。我需要这个代码，否则我可能有一个判断所有游戏的数据库的判断，如果一个游戏存在这个代码，我会添加它有点困难，这就是我来这里的原因。
我已将以下内容添加到我的控制器中：
[HttpPost]
public ActionResult Create(tblGame tblgame, HttpPostedFileBase image1, HttpPostedFileBase image2)
{
try
{
if (ModelState.IsValid)
{
var mygame = db.tblGames.Where(x => x.GameName == tblgame.GameName).SingleOrDefault();
if (mygame != null)
{
if (image1 != null)
{
string image = image1.FileName;
tblgame.Image = image;
var image1Path = Path.Combine(Server.MapPath("~/Content/UploadImages"), image);
image1.SaveAs(image1Path);
}
if (image2 != null)
{
string Image2 = image2.FileName;
tblgame.Image2 = Image2;
var image2Path = Path.Combine(Server.MapPath("~/Content/UploadImages"), Image2);
image2.SaveAs(image2Path);
}
db.tblGames.Add(tblgame);
db.SaveChanges();
return RedirectToAction("Index");
}
else
{
//otherwise we add a generic error to the model state
ModelState.AddModelError("", "A game review already exists");
}
}
}
catch
{
return View("Upload_Image_Failed");
}
//if arrive here the model is returned back to the view with the errors added
return View(tblgame);
}
答案 0 :(得分：3)
您可以使用Linq查询在保存之前检查游戏是否存在。 假设在我的示例中，字段名称足以识别您可以执行的游戏评论
[HttpPost]
public ActionResult Create(tblGame tblgame, HttpPostedFileBase image1, HttpPostedFileBase image2)
{
try
{
if (ModelState.IsValid)
{
var mygame = db.tblGames.Where(x => x.GameName == tblgame.GameName).SingleOrDefault();
if (mygame != null)
{
if (image1 != null)
{
string image = image1.FileName;
tblgame.Image = image;
var image1Path = Path.Combine(Server.MapPath("~/Content/UploadImages"), image);
image1.SaveAs(image1Path);
}
if (image2 != null)
{
string Image2 = image2.FileName;
tblgame.Image2 = Image2;
var image2Path = Path.Combine(Server.MapPath("~/Content/UploadImages"), Image2);
image2.SaveAs(image2Path);
}
db.tblGames.Add(tblgame);
db.SaveChanges();
//All ok, we redirect to index or to Edit method. (PRG pattern)
return RedirectToAction("Index");
}
else
{
//otherwise we add a generic error to the model state
ModelState.AddModelError("", "A game review already exists");
}
}
}
catch
{
//return View("Upload_Image_Failed");
ModelState.AddModelError("", "The upload of the images as failed");
}
//if we arrive here, the model is returned back to the view with the errors added
ViewBag.ConsoleNameIDFK = new SelectList(db.tblConsoles, "ConsoleName", "ConsoleName", tblgame.ConsoleNameIDFK);
return View(tblgame);
}
答案 1 :(得分：1)
根据您提供的代码，您应该更改Create操作方法：
[HttpPost]
public ActionResult Create(tblGame tblgame, // tblGame is the new game being created
HttpPostedFileBase image1,
HttpPostedFileBase image2)
{
try
{
if (ModelState.IsValid)
{
/* Go to DB and check if there's a Game already there that matches this
one just being added. What's the property you want to check against?
That's something you must provide. I just wrote GameName to show you
how to do this... */
var game = db.tblGames.Single(g => g.GameName == tblGame.GameName);
/* OK, can proceed adding this game... since there's no game in the DB
that matches this one being added. */
if (game == null)
{
// Continue saving the new game
}
else /* Abort and display a message to user informing that there's a game
already. */
{
// TODO
}
}
}
}
答案 2 :(得分：0)
我一直很努力地试图看看游戏是否已经过时了 我有使用户独特的代码。我需要这个代码，否则我 可能有一个判断所有游戏和数据库的数据 如果一个游戏已经使用此代码存在，我会添加一个错误 对我来说有点困难，这就是我来这里的原因。
每个用户都有自己独特的游戏列表，你就会得到一个名为GameMapping的表格，将每个用户映射到游戏中。
ID |用户ID |游戏ID
ID是您自动递增的主键。 UserID是链接到用户主ID的外键，GameID是链接到特定游戏的外键。
var user = GetUser(); // not sure what you use to identity users, but that logic would go here
var game = Db.Games.Where(g => g.Name == tblGame.Name).First();
Db.GameMapping
.Where(g => g.UserID == user.ID) // filter out all records for that user
.Select(g => g.GameID) // select just the game IDs
.Contains(game.ID) // see if the game id they want to add is in that list
这是一个替代LINQ查询，它执行相同的检查。
if (Db.GameMapping.Where(gm => gm.UserID == User.ID && gm.GameID == game.ID).Count() > 0)
// user already has that game
else
// they do not
看起来你的项目的增长开始引入错误并且变得有点压倒性。在项目中实现此游戏检查代码之前，我强烈建议首先设置一个小单元测试。创建一个与大项目分开的新项目，添加数据库并在游戏中创建一个非常小的测试，以及用户，并查看此代码是否按预期工作。一旦你知道你的实现是可靠的，那么将它集成到更大的项目中。
当你将项目分成小块并测试每一块时，你会大大降低调试整个过程的复杂性。祝你好运。