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Sort on multiple values with LINQ

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18 Sep 2010CPOL 18.8K   3   2

With LINQ sort, a collection with complex objects gets even easier than it was before. Simply use the OrderBy method of IEnumerable<T> which could look like follows:



C#
List<Person> personlist = new List<Person>() <br />{<br />    new Person(){ FirstName = "Peter", Name ="Muster", Age = 21}, <br />    new Person(){ FirstName = "Hans", Name = "Sampler", Age = 29}, <br />    new Person(){ FirstName = "Hans", Name ="Hood", Age = 34} <br />};<br /><br />IOrderedEnumerable<Person> sort = personlist.OrderBy(p => p.Age);<br />


But how can I sort on multiple values, say as example first sort on name and then on prenames, so all people with the same name are ordered by their prenames. Calling the GroupBy multiple times won't work. The answer is ThenBy.



C#
var multisort = list.OrderBy(p => p.FirstName).ThenBy(p => p.Name);<br /><br />foreach (Person person in multisort)<br />{<br />    Console.WriteLine("Name {0}, FirstName {1}, Age {2}",<br />        person.Name, person.FirstName, person.Age);<br />}<br />


ThenBy is an extension method of IOrderedEnumerable<T> which is returned by the OrderBy method. Both, the OrderBy and the ThenBy method will sort ascending, to sort descending, there are the methods OrderByDescending and ThenByDescending.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)



Comments and Discussions

 
GeneralMy vote of 4 Pin
Michael Bakker5-May-13 4:03
Michael Bakker5-May-13 4:03 
GeneralReason for my vote of 3 nothing excited Pin
maq_rohit10-Sep-10 20:49
professionalmaq_rohit10-Sep-10 20:49 
Reason for my vote of 3
nothing excited

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