Use of C # List

A, List Sort

　　Sort using custom comparator and Linq

class Persion
    {
        public string name;
        public int age;
}
//自定义Sort方法
private static void sortListClass()
        {
            Persion p1 = new Persion() { name = "huyong", age = 27 };
            Persion p2 = new Persion() { name = "tansha", age = 25 };
            List<Persion> listPersion = new List<Persion>();
            listPersion.Add(p1);
            listPersion.Add(p2);
            listPersion.Sort(sortage);
            foreach (var item in listPersion)
            {
                Console.WriteLine(item.name + ":" + item.age);
            }
        }
        static int sortage(Persion x, Persion y)
        {
            if (x.age < y.age) return -1;                //按age从大到小 降序排列
            else if (x.age == y.age) return 0;
            else return 1;
        }
//linq方法
 private static void sortLinq()
        {
            Persion p1 = new Persion() { name = "huyong", age = 27 };
            Persion p2 = new Persion() { name = "tansha", age = 25 };
            Persion p3 = new Persion() { name = "tansha", age = 27 };
            List<Persion> listPersion = new List<Persion>();
            listPersion.Add(p1);
            listPersion.Add(p2);
            listPersion.Add(p3);

 var lList = from t in listPersion where (t.age == 27) orderby t.name ascending select t;
            foreach (var item in lList)
            {
                Console.WriteLine(item.name + ":" + item.age);
            }
        }

View Code

 

Second, with the two Linq into one list list

  // LINQ two combined list, according to a same field 
Private  static  void mergeList () 
        { 
            persion P1 = new new persion () {name = " HY " , Province = " JX " }; 
            persion P2 = new new persion () {name = " tansha " , Province = " HN " }; 
            persion P3 = new new persion () {name = " HT " , Province = " Gd " };
            List<Persion> listPersion = new List<Persion>();
            listPersion.Add(p1);
            listPersion.Add(p2);
            listPersion.Add(p3);

            Persion p11 = new Persion() { name = "hy", age = 23, sex = "男" };
            Persion p21 = new Persion() { name = "tansha", age = 12, sex = "女" };
            Persion p31 = new Persion() { name = "ht", age = 7, sex = "男" };
            List<Persion> listPersion2 = new List<Persion>();
            listPersion2.Add(p11);
            listPersion2.Add(p21);
            listPersion2.Add(p31);

            //linq合并两个list,根据某一相同字段
            var list = from pp1 in listPersion
                       join pp2 in listPersion2 on pp1.name equals pp2.name
                       select new Persion
                       {
                           name = pp1.name,
                           province = pp1.province,
                           age = pp2.age,
                           sex = pp2.sex
                       };
            foreach (var item in list)
            {
                Console.WriteLine(item.name + ":" + item.age + ":" + item.sex + ":" + item.province);
            }
        }

View Code

 

Third, on the List a data inside the operation and save

lists.Where(q =>q.SellChannelId == ((int)SellChannelType.PB).ToString()).ToList().ForEach(q => q.index = 10);

Four, List <T> into IQueryable <T>

　　It can not be directly converted,

IQueryable query the database side,

IEnumerable query in memory.

List <T> to support the latter. Can be converted with list.AsQueryable <T>.