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MSDN Library

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
Assemblies:   System.Linq (in System.Linq.dll)
  System.Core (in System.Core.dll)

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

Type Parameters

TSource

The type of the elements of source.

Parameters

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

A sequence of values to determine the maximum value of.

selector
Type: System.Func<TSource, Int32>

A transform function to apply to each element.

Return Value

Type: System.Int32
The maximum value in the sequence.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<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 or selector is null.

InvalidOperationException

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);

                Console.WriteLine(
                    "The maximum pet age plus name length is {0}.",
                    max);
            }

            /*
             This code produces the following output:

             The maximum pet age plus name length is 14.
            */

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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