C# List中的GroupBy用法

setupInfoList是一个泛型集合List 

//pet为对象参数，可自定义；

JoinSetupid为我要分组的key

< IEnumerable> query = setupInfoList.GroupBy(pet => pet.JoinSetupid, pet => pet); 
foreach (IGrouping info in query) 
{ 
List sl=info.ToList();//分组后的集合 
//也可循环得到分组后，集合中的对象，你可以用info.Key去控制 
//foreach (KqiPageSetupInfo set in info)
 //{ 
//}
 }

http://blog.csdn.net/zyp_tfy/article/details/6122102

List排序的两种简便方式

///升序  
            List listCustomer1 = listCustomer.OrderBy(s => s.id).ToList();  
            //降序  
            List listCustomer2 = listCustomer.OrderByDescending(s => s.id).ToList();  
            //Linq排序方式  
            List listCustomer3 = (from c in listCustomer  
                                            orderby c.id descending //ascending  
                                            select c).ToList();  

http://blog.csdn.net/wanzhuan2010/article/details/6205884