Export (0) Print
Expand All

Queryable.Take<TSource> Method

Returns a specified number of contiguous elements from the start of a sequence.

Namespace:  System.Linq
Assembly:  System.Core (in System.Core.dll)

public static IQueryable<TSource> Take<TSource>(
	this IQueryable<TSource> source,
	int count
)

Type Parameters

TSource

The type of the elements of source.

Parameters

source
Type: System.Linq.IQueryable<TSource>
The sequence to return elements from.
count
Type: System.Int32
The number of elements to return.

Return Value

Type: System.Linq.IQueryable<TSource>
An IQueryable<T> that contains the specified number of elements from the start of source.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable<TSource>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

ExceptionCondition
ArgumentNullException

source is null.

The Take<TSource>(IQueryable<TSource>, Int32) method generates a MethodCallExpression that represents calling Take<TSource>(IQueryable<TSource>, Int32) itself as a constructed generic method. It then passes the MethodCallExpression to the CreateQuery(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

Take<TSource> enumerates source and yields elements until count elements have been yielded or source contains no more elements.

If count is less than or equal to zero, source is not enumerated and an empty IQueryable<T> is returned.

The query behavior that occurs as a result of executing an expression tree that represents calling Take<TSource>(IQueryable<TSource>, Int32) depends on the implementation of the type of the source parameter. The expected behavior is that it takes the first count elements from the start of source.

The following code example demonstrates how to use Take<TSource>(IQueryable<TSource>, Int32) to return elements from the start of a sequence.


            int[] grades = { 59, 82, 70, 56, 92, 98, 85 };

            // Sort the grades in descending order and take the first three.
            IEnumerable<int> topThreeGrades =
                grades.AsQueryable().OrderByDescending(grade => grade).Take(3);

            Console.WriteLine("The top three grades are:");
            foreach (int grade in topThreeGrades)
                Console.WriteLine(grade);

            /*
                This code produces the following output:

                The top three grades are:
                98
                92
                85
            */



.NET Framework

Supported in: 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Community Additions

ADD
Show:
© 2014 Microsoft