Navigation

• Home Page
• Advanced Search
• Categories
• All Pages (152)
• Recent Changes
• Resource links
• LINQ Books

5 Minute Overviews

• LINQ to Objects
• LINQ to SQL
• LINQ to XML

FAQ (new)

• LINQ to Objects
• LINQ to SQL
• LINQ to XML

Content

• Login/Logout
• Language Selection
• Your Profile
• Create Account

• Create a new Page
• File Management
• Editing Help
• Practise Editing
• About this Site
• Contact me

• Administration

{TOC}

Back to Standard Query Operator Index


Edit

Introduction

The OrderBy operator orders a sequence according to one or more keys in ascending order.

Edit

Method Signatures

// 1 - Order by keySelector
public static IOrderedSequence<TSource> OrderBy<TSource, TKey>(
    this IEnumerable<TSource> source, 
    Func<TSource, TKey> keySelector)
 
// 2 - Order by keySelector using custom comparer
public static IOrderedSequence<TSource> OrderBy<TSource, TKey>(
    this IEnumerable<TSource> source, 
    Func<TSource, TKey> keySelector, 
    IComparer<TKey> comparer)
 

Edit

Exception

Throws an ArgumentNullException if source or keySelector is null.

Edit

Pseudo-code

Overload 1
If source is null, throw an ArgumentNullException.
If keySelector is null, throw an ArgumentNullException.
Iterate the source sequence Iterate the buffer sequence.
Sort the buffer collection of keys using Quicksort algorithm.
Iterate the buffer collection, now sorted.

Overload 2 - custom comparer.
If source is null, throw an ArgumentNullException.
If keySelector is null, throw an ArgumentNullException.
If comparer is null, use Comparer<TKey>.Default; instead.
Iterate the source sequence.
Iterate the buffer sequence.
Sort the buffer collection of keys using Quicksort algorithm.
Iterate the buffer collection, now sorted.

Edit

Loop Count

2 - 2.5. A copy of the source elements is made, the keys evaluated, then the sequence is sorted via a Quicksort algorithm. This operator implements the standard deferred execution iterator pattern. This means, no looping will occur until the result is iterated over..

Edit

Code Samples

var qName = from n in db.tblNames
where n.DeletedFlag == false
orderby n.LastName,n.FirstName
select n;