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

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

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

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

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.

Type: System.Func<TSource, Double>

A transform function to apply to each element.

Return Value

Type: System.Double
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 or selector is null.


source contains no elements.

The Max<TSource>(IEnumerable<TSource>, Func<TSource, Double>) method uses the Double 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 Double.

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.


This code example uses an overload of this overloaded method that is different from the specific overload that this topic describes. To extend the example to this topic, change the body of the selector function.

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.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

Supported in: 3.5

.NET Compact Framework

Supported in: 3.5

XNA Framework

Supported in: 3.0
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