Max(TSource) Method (IEnumerable(TSource), Func(TSource, Int32))

Enumerable.Max<TSource> Method (IEnumerable<TSource>, Func<TSource, Int32>)


Invokes a transform function on each element of a sequence and returns the maximum Int32 value.

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

public static int Max<TSource>(
	this IEnumerable<TSource> source,
	Func<TSource, int> selector


Type: System.Collections.Generic.IEnumerable<TSource>

A sequence of values to determine the maximum value of.

Type: System.Func<TSourceInt32>

A transform function to apply to each element.

Return Value

Type: System.Int32

The maximum value in the sequence.

Type Parameters


The type of the elements of source.

Exception Condition

source or selector is null.


source contains no elements.

The Max<TSource>(IEnumerable<TSource>, Func<TSource, Int32>) method uses the Int32 implementation of IComparable<T> to compare values.

You can apply this method to a sequence of arbitrary values if you provide a function, selector, that projects the members of source into a numeric type, specifically Int32.

In Visual Basic query expression syntax, an Aggregate Into Max() clause translates to an invocation of Max.

The following code example demonstrates how to use Max<TSource>(IEnumerable<TSource>, Func<TSource, Int32>) to determine the maximum value in a sequence of projected values.

class Pet
    public string Name { get; set; }
    public int Age { get; set; }

public static void MaxEx4()
    Pet[] pets = { new Pet { Name="Barley", Age=8 },
                   new Pet { Name="Boots", Age=4 },
                   new Pet { Name="Whiskers", Age=1 } };

    int max = pets.Max(pet => pet.Age + pet.Name.Length);

        "The maximum pet age plus name length is {0}.",

 This code produces the following output:

 The maximum pet age plus name length is 14.

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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