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Enumerable.Max(Of TSource) Method (IEnumerable(Of TSource))


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Returns the maximum value in a generic sequence.

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

Public Shared Function Max(Of TSource) (
	source As IEnumerable(Of TSource)
) As TSource


Type: System.Collections.Generic.IEnumerable(Of TSource)

A sequence of values to determine the maximum value of.

Return Value

Type: TSource

The maximum value in the sequence.

Type Parameters


The type of the elements of source.

Exception Condition

source is null.

If type TSource implements IComparable(Of T), the Max(Of TSource)(IEnumerable(Of 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(Of TSource)(IEnumerable(Of TSource)) to determine the maximum value in a sequence of IComparable(Of T) objects.

' This class implements IComparable 
' and has a custom 'CompareTo' implementation.
Class Pet
    Implements IComparable(Of Pet)

    Public Name As String
    Public Age As Integer

    ''' <summary>
    ''' Compares Pet objects by the sum of their age and name length.
    ''' </summary>
    ''' <param name="other">The Pet to compare this Pet to.</param>
    ''' <returns>-1 if this Pet's sum is 'less' than the other Pet,
    ''' 0 if they are equal,
    ''' or 1 if this Pet's sum is 'greater' than the other Pet.</returns>
    Function CompareTo(ByVal other As Pet) As Integer _
    Implements IComparable(Of Pet).CompareTo

        If (other.Age + other.Name.Length > Me.Age + Me.Name.Length) Then
            Return -1
        ElseIf (other.Age + other.Name.Length = Me.Age + Me.Name.Length) Then
            Return 0
            Return 1
        End If
    End Function
End Class

Sub MaxEx3()
    ' 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}}

    ' Find the "maximum" pet according to the 
    ' custom CompareTo() implementation.
    Dim max As Pet = pets.Max()

    ' Display the result.
    MsgBox("The 'maximum' animal is " & max.Name)
End Sub

' This code produces the following output:
' The 'maximum' animal is Barley

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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