c#.net ef 框架的基础操作

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Reflection; namespace MCO.EF { public class Test { //实例化上下文
        ConnectionSQL connection = new ConnectionSQL(); //增加
        public int DataAdd() { User user = new User() { UserName = "陆六", UserSex = true }; connection.User.Add(user); return connection.SaveChanges(); } //删除
        public int Delete() { List<User> user = connection.User.Where<User>(u => u.UserId > 2).ToList<User>(); foreach(User u in user) { connection.User.Remove(u); } return connection.SaveChanges(); } //修改
        public int Update() { List<User> user =  connection.User.Where<User>(u => u.UserSex == true).ToList<User>(); foreach(User u in user) { u.UserSex = false; } return connection.SaveChanges(); } //查询
        private void UserList() { IQueryable userList = connection.User.Where<User>(u => u.UserId > 1); //反射获取实体类的所有属性值和属性名
            PropertyInfo[] attribute = typeof(User).GetProperties(); //调用 ListToJson 方法
 Console.Write(ListToJson(attribute, userList)); } //反射拼接成 json
        private string ListToJson(PropertyInfo[] attribute, IQueryable dataList) { StringBuilder strJson = new StringBuilder(256); foreach(var data in dataList) { strJson.Append("{"); for(int i = 0; i < attribute.Length; i++) { //获取属性名 和 属性值(通过反射)
                    strJson.AppendFormat("\"{0}\":\"{1}\",", attribute[i].Name, attribute[i].GetValue(data)); } strJson.Remove(strJson.Length - 1, 1); strJson.Append("},"); } strJson.Remove(strJson.Length - 1, 1); return strJson.ToString(); } } }