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

Returns the maximum value in a generic sequence.

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

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

Type Parameters


The type of the elements of 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).


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;
                        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();

                    "The 'maximum' animal is {0}.",

             This code produces the following output:

             The 'maximum' animal is Barley.

.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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