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Enumerable.Max<TSource> Method (IEnumerable<TSource>)

Returns the maximum value in a generic sequence.

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

public static TSource Max<TSource>(
	this IEnumerable<TSource> source
)

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.

Return Value

Type: TSource
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 is null.

If type TSource implements IComparable<T>, the Max<TSource>(IEnumerable<TSource>) method uses that implementation to compare values. Otherwise, if type TSource implements IComparable, that implementation is used to compare values.

If TSource is a reference type and the source sequence is empty or contains only values that are null, this method returns null.

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>) to determine the maximum value in a sequence of IComparable<T> objects.

            /// <summary> 
            /// This class implements IComparable to be able to  
            /// compare one Pet to another Pet. 
            /// </summary> 
            class Pet : IComparable<Pet>
            {
                public string Name { get; set; }
                public int Age { get; set; }

                /// <summary> 
                /// Compares this Pet to another Pet by  
                /// summing each Pet's age and name length. 
                /// </summary> 
                /// <param name="other">The Pet to compare this Pet to.</param>
                /// <returns>-1 if this Pet is 'less' than the other Pet,  
                /// 0 if they are equal, 
                /// or 1 if this Pet is 'greater' than the other Pet.</returns> 
                int IComparable<Pet>.CompareTo(Pet other)
                {
                    int sumOther = other.Age + other.Name.Length;
                    int sumThis = this.Age + this.Name.Length;

                    if (sumOther > sumThis)
                        return -1;
                    else if (sumOther == sumThis)
                        return 0;
                    else 
                        return 1;
                }
            }

            public static void MaxEx3()
            {
                Pet[] pets = { new Pet { Name="Barley", Age=8 },
                               new Pet { Name="Boots", Age=4 },
                               new Pet { Name="Whiskers", Age=1 } };

                Pet max = pets.Max();

                Console.WriteLine(
                    "The 'maximum' animal is {0}.",
                    max.Name);
            }

            /*
             This code produces the following output:

             The 'maximum' animal is Barley.
            */

.NET Framework

Supported in: 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

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

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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