C# MVC模式下商品抽奖功能实现

 <div class="turntable-bg">
       
          <div class="pointer">
            <img id="pointer" src="~/Content/images/pointer.png" alt="pointer" />
          </div>
          <div class="rotate">
            <img id="turntable" src="~/Content/images/turntable.png" alt="turntable" />
          </div>
        </div>

function rotate() {
    $.ajax({
      type: 'POST',
      url: '/控制器/方法',
      dataType: 'json',
      cache: false,
      error: function () {
        alert('出错了！');
        return false;
      },
      success: function (data) {
        if (data == 1 || data == -3) {
          var bRotate = true;
          if (data == 1) {
            alert("请登录!");
          }if (data == -3) {
            alert("对不起，您的奖券不足!")
          }
        }
        else {
          var angles = parseInt(data.angle); //角度  
          var txt = data.prize; //奖项  
          var awards = parseInt(data.id);
          var bRotate = false; //如果bRotate为 true 的时候无法点击
          var rotateFn = rotateFn_method(awards, angles, txt);

          if (bRotate) return;

          switch (awards) {
            case 0:
              //var angle = [26, 88, 137, 185, 235, 287, 337];
　　　　　　　　　　　　　　　　// rptateFn_method 三个参数均为后台传出，0,337  为转盘旋转所对应的角度，最后一个则为商品名称

              rotateFn_method(0, 337, '奖品名称');
              break;
            case 1:
              //var angle = [88, 137, 185, 235, 287];
              rotateFn_method(1, 26, '奖品名称');
                break;
              case 2:
                //var angle = [137, 185, 235, 287];
                rotateFn_method(2, 88, '奖品名称');
              break;
            case 3:
              //var angle = [137, 185, 235, 287];
              rotateFn_method(3, 137, '奖品名称');
              break;
            case 4:
              //var angle = [185, 235, 287];
              rotateFn_method(4, 185, '奖品名称');
              break;
            case 5:
              //var angle = [185, 235, 287];
              rotateFn_method(5, 235, '奖品名称');
              break;
            case 6:
              //var angle = [235, 287];
              rotateFn_method(6, 235, '奖品名称');
              break;
            case 7:
              //var angle = [287];
              rotateFn_method(7, 282, '奖品名称');
              break;
          }
        }

      }
    });
  }

　　//旋转事件
  function rotateFn_method(awards, angles, txt) {
    var bRotate = false;
    bRotate = !bRotate;
    $('#turntable').stopRotate();
    $('#turntable').rotate({
      angle: 0,
      animateTo: angles + 1800,
      duration: 8000,
      callback: function () {
          $("#Pl h4").html("恭喜你抽中" + txt + "");
        }
        bRotate = !bRotate;
      }
    })
  };
//刷新当前页面
  function locateEnd() {
    window.location.reload();
  }

//判断用户是否登录 
      if (admin != null)
      {
　　　　　　　　　//获取后台设置的数据，见图1
        var LdList = hr.LuckdrawList();
　　　　　　　　　//因为涉及到公司的项目所有一些敏感地方均已中文代替
        List<double> dt = LdList.Select(i => i.概率).ToList();
　　　　　　　　　//创建一个数值
        double[] Array = dt.ToArray();
        //角度
        int angle = 0;
        //奖品
        var prize = "";
        var id = 0;
　　　　　　　　　//将概率放入数值，调用下面的Get方法计算出所返回的概率位于数值中的第几位
        var Pl = Get(Array);
　　　　　　　　　//获取奖品表中位于Pl的产品
        var model = LdList[Pl];
　　　　　　　　　　　// id , angle 角度  prize 奖品
if (model.奖品等级 == 1)
          {
            angle = 26;
            prize = model.奖品;
            id = 1;
          }
          if (model.奖品等级 == 7)
          {
            angle = 88;
            prize = model.奖品;
            id = 2;
          }
          if (model.奖品等级 == 4)
          {
            angle = 137;
            prize = model.奖品;
            id = 3;
          }
          if (model.奖品等级 == 3)
          {
            angle = 185;
            prize = model.奖品;
            id = 4;
          }
          if (model.奖品等级 == 6)
          {
            angle = 235;
            prize = model.奖品;
            id = 5;
          }
          if (model.奖品等级 == 2)
          {
            angle = 282;
            prize = model.奖品;
            id = 7;
          }
          if (model.奖品等级 == 5)
          {
            angle = 337;
            prize = model.奖品;
            id = 0;
          }
          return Json(new { angle = angle, prize = prize, id = id });
        }return Json(data);
      }

/// <summary>
    /// 获取抽奖结果
    /// </summary>
    /// <param name="prob">各物品的抽中概率</param>
    /// <returns>返回抽中的物品所在数组的位置</returns>
    private static int Get(double[] prob)
    {
      int result = 0;
      int n = (int)(prob.Sum() * 1000);      //计算概率总和，放大1000倍
      Random r = rnd;
      float x = (float)r.Next(0, n) / 1000;    //随机生成0~概率总和的数字

      for (int i = 0; i < prob.Count(); i++)
      {
        double pre = prob.Take(i).Sum();     //区间下界
        double next = prob.Take(i + 1).Sum();  //区间上界
        if (x >= pre && x < next)        //如果在该区间范围内，就返回结果退出循环
        {
          result = i;
          break;
        }
      }
      return result;
    }
    private static Random rnd = new Random();