C# 获取List对象操作-查询属性、字段值合并、分组.......

            List<Model> strList = new List<Model>()
            {
                new Model(){Id=1,Name = "张三"},
                new Model(){Id=11,Name = "张三1"},
                new Model(){Id=2,Name = "李四"},
                new Model(){Id=3,Name = "王五"},
                new Model(){Id=30,Name = "王五"},
                new Model(){Id=4,Name = "赵六"},
            };
            //查询List对象某个字段
            var names = strList.Select(t => t.Name).ToList();
            //字段值合并
            string mergeName = string.Join("|", names.ToArray());                        

 

//根据某个字段分组  
var types = strList.GroupBy(x => x.Name)
                      .Select(group => new Model
                      {
                          Name = group.Key,
                      }).ToList();

 //List中实现类似SQL 查询  select in...

            List<int> whereList = new List<int>() { 1, 3 };
            List<Model> list = strList.Where(x => whereList.Contains(x.Id)).ToList();

            foreach (var model in list)
            {
                Console.WriteLine("Id:" + model.Id + "Name:" + model.Name);
            }
            Console.WriteLine("list count==" + list.Count);    

　

//更改list中某个字段
list.ForEach(o => o.Age = 33);

list.All(o => { o.Age = 22; return true; });

//List中获取最大值
int maxA = list.Max(x => x.A);//获取链表中对象属性A的最大值

　数组、list转化

List<string> listS=new List<string>();
listS.Add("str");
listS.Add("hello");
string[] str=listS.ToArray();

string[] stauts = dict[0].SDValue.Split('|');
List<string> tempStatus = new List<string>(stauts);
where = where.And(o => tempStatus.Contains(o.STATUS));