Queryable.OrderBy Method
Definition
Important
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Sorts the elements of a sequence in ascending order.
Overloads
| OrderBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) |
Sorts the elements of a sequence in ascending order by using a specified comparer. |
| OrderBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>) |
Sorts the elements of a sequence in ascending order according to a key. |
OrderBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>)
- Source:
- Queryable.cs
- Source:
- Queryable.cs
- Source:
- Queryable.cs
Sorts the elements of a sequence in ascending order by using a specified comparer.
public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
static System::Linq::IOrderedQueryable<TSource> ^ OrderBy(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, TKey> ^> ^ keySelector, System::Collections::Generic::IComparer<TKey> ^ comparer);public static System.Linq.IOrderedQueryable<TSource> OrderBy<TSource,TKey> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector, System.Collections.Generic.IComparer<TKey> comparer);public static System.Linq.IOrderedQueryable<TSource> OrderBy<TSource,TKey> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector, System.Collections.Generic.IComparer<TKey>? comparer);static member OrderBy : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, 'Key>> * System.Collections.Generic.IComparer<'Key> -> System.Linq.IOrderedQueryable<'Source><Extension()>
Public Function OrderBy(Of TSource, TKey) (source As IQueryable(Of TSource), keySelector As Expression(Of Func(Of TSource, TKey)), comparer As IComparer(Of TKey)) As IOrderedQueryable(Of TSource)Type Parameters
- TSource
The type of the elements of source.
- TKey
The type of the key returned by the function that is represented by keySelector.
Parameters
- source
- IQueryable<TSource>
A sequence of values to order.
- keySelector
- Expression<Func<TSource,TKey>>
A function to extract a key from an element.
- comparer
- IComparer<TKey>
An IComparer<T> to compare keys.
Returns
An IOrderedQueryable<T> whose elements are sorted according to a key.
Exceptions
source or keySelector or comparer is null.
Remarks
This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.
The OrderBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) method generates a MethodCallExpression that represents calling OrderBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) itself as a constructed generic method. It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter. The result of calling CreateQuery<TElement>(Expression) is cast to type IOrderedQueryable<T> and returned.
The query behavior that occurs as a result of executing an expression tree that represents calling OrderBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>, IComparer<TKey>) depends on the implementation of the type of the source parameter. The expected behavior is that it sorts the elements of source based on the key obtained by invoking keySelector on each element of source. The comparer parameter is used to compare keys.
Applies to
OrderBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>)
- Source:
- Queryable.cs
- Source:
- Queryable.cs
- Source:
- Queryable.cs
Sorts the elements of a sequence in ascending order according to a key.
public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
static System::Linq::IOrderedQueryable<TSource> ^ OrderBy(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, TKey> ^> ^ keySelector);public static System.Linq.IOrderedQueryable<TSource> OrderBy<TSource,TKey> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector);static member OrderBy : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, 'Key>> -> System.Linq.IOrderedQueryable<'Source><Extension()>
Public Function OrderBy(Of TSource, TKey) (source As IQueryable(Of TSource), keySelector As Expression(Of Func(Of TSource, TKey))) As IOrderedQueryable(Of TSource)Type Parameters
- TSource
The type of the elements of source.
- TKey
The type of the key returned by the function that is represented by keySelector.
Parameters
- source
- IQueryable<TSource>
A sequence of values to order.
- keySelector
- Expression<Func<TSource,TKey>>
A function to extract a key from an element.
Returns
An IOrderedQueryable<T> whose elements are sorted according to a key.
Exceptions
source or keySelector is null.
Examples
The following code example demonstrates how to use OrderBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>) to sort the elements of a sequence.
class Pet
{
public string Name { get; set; }
public int Age { get; set; }
}
public static void OrderByEx1()
{
Pet[] pets = { new Pet { Name="Barley", Age=8 },
new Pet { Name="Boots", Age=4 },
new Pet { Name="Whiskers", Age=1 } };
// Sort the Pet objects in the array by Pet.Age.
IEnumerable<Pet> query =
pets.AsQueryable().OrderBy(pet => pet.Age);
foreach (Pet pet in query)
Console.WriteLine("{0} - {1}", pet.Name, pet.Age);
}
/*
This code produces the following output:
Whiskers - 1
Boots - 4
Barley - 8
*/
Structure Pet
Public Name As String
Public Age As Integer
End Structure
Shared Sub OrderByEx1()
Dim pets() As Pet = {New Pet With {.Name = "Barley", .Age = 8}, _
New Pet With {.Name = "Boots", .Age = 4}, _
New Pet With {.Name = "Whiskers", .Age = 1}}
' Sort the Pet objects in the array by Pet.Age.
Dim query As IEnumerable(Of Pet) = _
pets.AsQueryable().OrderBy(Function(pet) pet.Age)
Dim output As New System.Text.StringBuilder
For Each pet As Pet In query
output.AppendLine(String.Format("{0} - {1}", pet.Name, pet.Age))
Next
' Display the output.
MsgBox(output.ToString())
End Sub
' This code produces the following output:
' Whiskers - 1
' Boots - 4
' Barley - 8
Remarks
This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.
The OrderBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>) method generates a MethodCallExpression that represents calling OrderBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>) itself as a constructed generic method. It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter. The result of calling CreateQuery<TElement>(Expression) is cast to type IOrderedQueryable<T> and returned.
The query behavior that occurs as a result of executing an expression tree that represents calling OrderBy<TSource,TKey>(IQueryable<TSource>, Expression<Func<TSource,TKey>>) depends on the implementation of the type of the source parameter. The expected behavior is that it sorts the elements of source based on the key obtained by invoking keySelector on each element of source.
