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EnumerableMax Method

Invokes a transform function on each element of a sequence and returns the maximum nullable Int64 value.

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

public static Nullable<long> Max<TSource>(
	this IEnumerable<TSource> source,
	Func<TSource, Nullable<long>> selector
generic<typename TSource>
static Nullable<long long> Max(
	IEnumerable<TSource>^ source,
	Func<TSource, Nullable<long long>>^ selector
static member Max<'TSource> : 
        source:IEnumerable<'TSource> *
        selector:Func<'TSource, Nullable<int64>> -> Nullable<int64>
Public Shared Function Max(Of TSource) (
	source As IEnumerable(Of TSource),
	selector As Func(Of TSource, Nullable(OfLong))
) As Nullable(OfLong)



A sequence of values to determine the maximum value of.


A transform function to apply to each element.

Return Value


The value of type Nullable<Int64> in C# or Nullable(Of Int64) in Visual Basic that corresponds to the maximum value in the sequence.

Type Parameters


The type of the elements of source.

Exception Condition

source or selector is null.


The Max method uses the Int64 implementation of IComparable 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 Nullable<Int64> in C# or Nullable(Of Int64) in Visual Basic.

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 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.
Structure Pet
    Public Name As String
    Public Age As Integer
End Structure

Sub MaxEx4()
    ' Create an array of Pet objects.
    Dim pets() As Pet = {New Pet With {.Name = "Barley", .Age = 8}, _
                         New Pet With {.Name = "Boots", .Age = 4}, _
                         New Pet With {.Name = "Whiskers", .Age = 1}}

    ' Determine the "maximum" pet by passing a
    ' lambda expression to Max() that sums the pet's age
    ' and name length.
    Dim max As Integer = pets.Max(Function(pet) _
                                      pet.Age + pet.Name.Length)

    ' Display the result.
    MsgBox("The maximum pet age plus name length is " & max)
End Sub

' This code produces the following output:
' The maximum pet age plus name length is 14
Version Information
Universal Windows Platform
Available since 8
.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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