如何在选定值后从下拉列表中清除该值

大家好，我想要一种方法，当用户从下拉列表中选择一个值并输入界面上的值时，下拉列表中的值将被清除，无法再选择。

这是我的型号：

namespace Game.Models
{
    using System;
    using System.Collections.Generic;
    public partial class tblReview
    {
        public int ReviewID { get; set; }
        public string Recomendation { get; set; }
        public string AvoidOrBuy { get; set; }
        public string Score { get; set; }
        public int GameIDFK { get; set; }
        public string UserName { get; set; }
        public virtual tblGame tblGame { get; set; }
    }
}

这是我的控制器：

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using Game.Models;
namespace Game.Controllers
{ 
    public class ReviewController : Controller
    {
        private gamezoneDBEntities db = new gamezoneDBEntities();
        //
        // GET: /Review/
        public ViewResult Index()
        {
            var Info = db.tblReviews.Include(x => x.tblGame).Where(UserInfo => UserInfo.UserName.Equals(User.Identity.Name)).ToList();
            return View(Info); 
        }
        //
        // GET: /Review/Details/5
        public ViewResult Details(int id)
        {
            tblReview tblreview = db.tblReviews.Find(id);
            return View(tblreview);
        }
        //
        // GET: /Review/Create
        public ActionResult Create()
        {
            var userGames = db.tblGames.Where(g => g.UserName == User.Identity.Name);
            ViewBag.GameIDFK = new SelectList(userGames, "GameID", "GameName");
            return View(new tblReview { UserName = @User.Identity.Name });
        } 
        //
        // POST: /Review/Create
        [HttpPost]
        public ActionResult Create(tblReview tblreview)
        {
            if (ModelState.IsValid)
            {
                db.tblReviews.Add(tblreview);
                db.SaveChanges();
                return RedirectToAction("Index");  
            }
            var userGames = db.tblGames.Where(g => g.UserName == User.Identity.Name);
            ViewBag.GameIDFK = new SelectList(userGames, "GameID", "GameName");
            return View(new tblReview { UserName = @User.Identity.Name });
        }
        //
        // GET: /Review/Edit/5
        public ActionResult Edit(int id)
        {
            tblReview tblreview = db.tblReviews.Find(id);
            ViewBag.GameIDFK = new SelectList(db.tblGames, "GameID", "GameName", tblreview.GameIDFK);
            return View(tblreview);
        }
        //
        // POST: /Review/Edit/5
        [HttpPost]
        public ActionResult Edit(tblReview tblreview)
        {
            if (ModelState.IsValid)
            {
                db.Entry(tblreview).State = EntityState.Modified;
                db.SaveChanges();
                return RedirectToAction("Index");
            }
            ViewBag.GameIDFK = new SelectList(db.tblGames, "GameID", "GameName", tblreview.GameIDFK);
            return View(tblreview);
        }
        //
        // GET: /Review/Delete/5
        public ActionResult Delete(int id)
        {
            tblReview tblreview = db.tblReviews.Find(id);
            return View(tblreview);
        }
        //
        // POST: /Review/Delete/5
        [HttpPost, ActionName("Delete")]
        public ActionResult DeleteConfirmed(int id)
        {            
            tblReview tblreview = db.tblReviews.Find(id);
            db.tblReviews.Remove(tblreview);
            db.SaveChanges();
            return RedirectToAction("Index");
        }
        protected override void Dispose(bool disposing)
        {
            db.Dispose();
            base.Dispose(disposing);
        }
    }
}

这是一个视图：

@model Game.tblReview
@{
    ViewBag.Title = "Create";
}
<h2>Create</h2>
<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>
@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)
    <fieldset>
        <legend>tblReview</legend>
        <div class="editor-label">
            @Html.LabelFor(model => model.ReviewID)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.ReviewID)
            @Html.ValidationMessageFor(model => model.ReviewID)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.Recomendation)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Recomendation)
            @Html.ValidationMessageFor(model => model.Recomendation)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.AvoidOrBuy)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.AvoidOrBuy)
            @Html.ValidationMessageFor(model => model.AvoidOrBuy)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.Score)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Score)
            @Html.ValidationMessageFor(model => model.Score)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.GameIDFK, "tblGame")
        </div>
        <div class="editor-field">
            @Html.DropDownList("GameIDFK", String.Empty)
            @Html.ValidationMessageFor(model => model.GameIDFK)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.UserName)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.UserName)
            @Html.ValidationMessageFor(model => model.UserName)
        </div>
        <p>
            <input type="submit" value="Create" />
        </p>
    </fieldset>
}
<div>
    @Html.ActionLink("Back to List", "Index")
</div>

将非常感谢您的帮助

如果有什么需要的，请询问。

 <div class="editor-field">
                @Html.DropDownList("GameIDFK", String.Empty)
                @Html.ValidationMessageFor(model => ViewBag.GameIDFK)
            </div>

    [HttpPost]
    public ActionResult Create(tblReview tblreview, FormCollection formCollection)
       {
                if (ModelState.IsValid)
                {
                    db.tblReviews.Add(tblreview);
                    db.SaveChanges();
                   // return RedirectToAction("Index");  
                }
                 int gameid=Convert.ToInt32(formCollection["GameIDFK"]);
                var userGames = (from g in db.tblGames where g.UserName== User.Identity.Name && g.GameID!=gameid select g).ToList();
                ViewBag.GameIDFK = new SelectList(userGames, "GameID", "GameName");
                return View(new tblReview { UserName = @User.Identity.Name });
    }