LINQ----1

Student[] stAry ={

                              new Student("张三","男",),

                              new Student("小明","男",),

                              new Student("丽丽","女",),

                              new Student("小菊","女",),

                              new Student("张四","男",),

                              new Student("张八","男",),

                          };

            var query1 = from vall in stAry

                         select vall;

            foreach (Student st in query1)

                System.Console.WriteLine(st);

            var query2 = from val2 in stAry select val2.Age;

            foreach (var age in query2)

            {

                System.Console.WriteLine("{0}",age);

            }

            var query3 = from val2 in stAry select val2.Name.Length ;

            foreach (var name in query3)

            {

                System.Console.WriteLine(name);

            }

where 的用法：

int[] ary = { , , , , , , , , , ,  };

            var query1 = from val1 in ary where val1 >  select val1;

            foreach (var val in query1)

                System.Console.WriteLine(val);

orderby的用法：

Student [] stary=

            {

                 new Student ("王小二","男",),

                 new Student ("张武率军","男",),

                  new Student ("徐暾于灏","男",),

                  new Student ("一朵鲜花","女",),

            };

            var query1 = from val1 in stary

                         orderby val1.Age

                         select val1;

            foreach (var st in query1)

            {

                System.Console.WriteLine("{0}--{1}--{2}", st.Name, st.XingBie, st.Age);

            }

默认为升序，ascending，可以设置为降序 desending。

可以指定多个关键字

如果同一个查询中出现多个orderby，则只有最后一个有效。与where的取并集的效果不同。

用group 分组：

var query1 = from st in stary

                         group st by st.XingBie;

            foreach (var grp in query1)

            {

                System.Console.WriteLine(grp.Key);

                foreach(var stu in grp)

                {

                    System.Console.WriteLine(stu);

                }

            }

            var query2 = from st in stary

                         group st by st.Age into stgrp_age

                         select stgrp_age;

            foreach(var age in query2)

            {

                System.Console.WriteLine(age.Key + ":");

                foreach(var stu in age)

                {

                    System.Console.WriteLine(stu);

                }

            }

巴特西

LINQ----1

最新文章

热门文章