linq to object 未完待续
1.linq to string
string s2 = "abc";
var data2 = s2.Where(x => x.CompareTo('a') > 0).ToList();
string s3 = "";
data2.ForEach(a => { s3 += a.ToString(); });
2. linq to datatable
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication8
{
public class Student
{
public int No { get; set; }
public string Name { get; set; }
public int Age { get; set; }
}
class Program
{
static void Main(string[] args)
{
//TestDb2Entities1 DbContext = new TestDb2Entities1();
//var stu = (from s in DbContext.UserInfoSets where s.Id == 1 select s).First();
//RoleInfoSet r = stu.RoleInfoSets.ToList()[0];
//DataTable table=new DataTable();
//var t = from s in table.AsEnumerable() group s by s.Field<Int32>("") into g select g;
DataTable table = new DataTable();
table.Columns.Add("Id", typeof(Int32));
table.Columns.Add("Name", typeof(String));
table.Columns.Add("Age", typeof(Int32));
DataRow row = table.NewRow();
row["Id"] = 1;
row["Name"] = "1";
row["Age"] = 10;
table.Rows.Add(row);
row = table.NewRow();
row["Id"] = 2;
row["Name"] = "2";
row["Age"] = 2;
table.Rows.Add(row);
row = table.NewRow();
row["Id"] = 1;
row["Name"] = "3";
row["Age"] = 3;
table.Rows.Add(row);
//var stus = from s in table.AsEnumerable() group s by s.Field<Int32>("Id") into g select
//new {
// key=g.Key,value=g
//}
//;
var stus = from s in table.AsEnumerable()
where s.Field<Int32>("Id") == 1
group s by s.Field<Int32>("Id")
into g
select g;
var list = stus.ToList();
var c = list[0].ToList()[1].Field<Int32>("Age");
Console.ReadKey();
}
}
}
3.待续
最新文章
- javascript实现json页面分页
- R语言学习笔记-变量的作用域
- Understanding Asynchronous IO With Python 3.4&#39;s Asyncio And Node.js
- .net对各表的操作详细到字段的更改记录的日志
- JAVA实例化class的三种方式
- Hive基础学习
- 201521123015 《Java程序设计》第七周学习总结
- Hadoop(三)手把手教你搭建Hadoop全分布式集群
- Tomcat针对网站打开速度慢进行局部优化方案
- SSH批量管理 expect自动交互
- 更改一个链接的文本、URL 以及 target
- ARCGIS 数据格式
- webapi发布到windows 2012的iis8里 出错
- js动态修改Easyui元素不生效,EasyUI动态渲染解析解决方案
- 半自动代码生成--方式C#
- zkClient的使用
- express安装及使用(windows系统)
- 14 MySQL--事务&;函数与流程控制
- 填报表导出excel非可写单元格锁定问题
- C语言 &#183; 素数求和