在Common文件中创建BaseModel

    public class BaseModel<T> where T : class, new()
    {
        /// <summary>
        /// 获取上下文
        /// </summary>
        /// <returns>EF上下文</returns>
        public static DemoContext Create()
        {
            DemoContext db = CallContext.GetData("db") as DemoContext;
            if (db == null)
            {
                db = new DemoContext();
                CallContext.SetData("db", db);
            }
            return db;
        }

        /// <summary>
        /// 上下文
        /// </summary>
        DemoContext db = Create();

        /// <summary>
        /// 查询数据,IQueryable延迟加载集合，调用时才会去加载至内存,List查询后会立即加载至内存中
        /// </summary>
        /// <param name="whereLambda">查询条件</param>
        /// <returns>数据集合</returns>
        public IQueryable<T> GetList(Expression<Func<T, bool>> whereLambda)
        {
            return db.Set<T>().Where(whereLambda);
        }

        public int Add(T entity)
        {
            db.Set<T>().Add(entity);
            return db.SaveChanges();

        }

        public int Delete(int id)
        {
            //通过ID查询这条实体
            T entity = db.Set<T>().Find(id);
            db.Set<T>().Remove(entity);
            return db.SaveChanges();
        }

        public int Update(T entity)
        {
            //设置当前实体的状态为修改
            db.Entry(entity).State = System.Data.Entity.EntityState.Modified;
            return db.SaveChanges();
        }
    }

 在Common中创建HttpRequestHelper

    public class HttpRequestHelper
    {
        public static string HttpGet(string url)
        {
            string result = string.Empty;
            try
            {
                HttpWebRequest wbRequest = (HttpWebRequest)WebRequest.Create(url);
                wbRequest.Method = "GET";
                HttpWebResponse wbResponse = (HttpWebResponse)wbRequest.GetResponse();
                using (Stream responseStream = wbResponse.GetResponseStream())
                {
                    using (StreamReader sReader = new StreamReader(responseStream))
                    {
                        result = sReader.ReadToEnd();
                    }
                }
            }
            catch (Exception ex)
            {

            }
            return result;
        }

        public static string HttpPost(string url, string paramData, Dictionary<string, string> headerDic = null)
        {
            string result = string.Empty;
            try
            {
                HttpWebRequest wbRequest = (HttpWebRequest)WebRequest.Create(url);
                wbRequest.Method = "POST";
                wbRequest.ContentType = "application/x-www-form-urlencoded";
                wbRequest.ContentLength = Encoding.UTF8.GetByteCount(paramData);
                if (headerDic != null && headerDic.Count > 0)
                {
                    foreach (var item in headerDic)
                    {
                        wbRequest.Headers.Add(item.Key, item.Value);
                    }
                }
                using (Stream requestStream = wbRequest.GetRequestStream())
                {
                    using (StreamWriter swrite = new StreamWriter(requestStream))
                    {
                        swrite.Write(paramData);
                    }
                }
                HttpWebResponse wbResponse = (HttpWebResponse)wbRequest.GetResponse();
                using (Stream responseStream = wbResponse.GetResponseStream())
                {
                    using (StreamReader sread = new StreamReader(responseStream))
                    {
                        result = sread.ReadToEnd();
                    }
                }
            }
            catch (Exception ex)
            { }
            return result;
        }
    }

全局变量globalData在app.js页面和其他js页面调用与修改问题

全局变量globalData

小程序中js页面声明的变量与函数只能在此页面中使用，并且在不同页面中可以用相同的变量命名。而如果想要某些数据在所有页面中都能使用，那就可以使用全局变量globalData进行数据的存取。globalData在app.js中进行设置。

//app.js文件
App({
  //在小程序完成初始化时，触发onLaunch(全局只触发一次)
  // Do something initial when launch.
  onLaunch(options) {

  },
  //全局变量
  globalData: {
    Info: 12,
    newsList: [{}]
  }
})

一、app.js页面中globalData变量的修改

1、在app.js页面中要修改globalData变量的值，如果直接在onLaunch: function () 函数中修改，只需要用this调用globalData进行修改。

this.globalData.Info = 15;
console.log(this.globalData.Info) //15

2、若使用了请求wx.request等 则需要使用 var that = this，然后用that调用globalData。

//app.js文件
App({
  //在小程序完成初始化时，触发onLaunch(全局只触发一次)
  // Do something initial when launch.
  onLaunch(options) {
    //请求信息
    var that = this;
    wx.request({
      url: 'https:', //此处略
      data: {
        x: "",
        y: ""
      },
      success: function (res) {
        console.log(res.data);
        let list = [];
        for (var i = 0; i < 4; i++) {
          let obj = {};
          obj.id = res.data.result.data[i].uniquekey;
          obj.title = res.data.result.data[i].title;
          obj.date = res.data.result.data[i].date;
          obj.url = res.data.result.data[i].url;
          obj.poster = res.data.result.data[i].thumbnail_pic_s;
          list.push(obj);
        }
        that.globalData.newsList = list;
      }
    })
  },
  //全局变量
  globalData: {
    Info: 12,
    newsList: [{}]
  }
})

二、其他js页面中globalData变量的读取和修改

当需要在其他页面读取和修改globalData中的数据时，需要用var app = getApp()进行引用

1、读取

var app = getApp(); //声明app实例
Page({
  onl oad: function () {
    console.log(app.globalData.Info);
  }
})

2、修改数据

var app = getApp();
Page({
  onl oad: function () {
    app.globalData.Info = 22;
  }
})