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

Returns the maximum value in a generic sequence.

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

<ExtensionAttribute> _
Public Shared Function Max(Of TSource) ( _
	source As IEnumerable(Of TSource) _
) As TSource
Dim source As IEnumerable(Of TSource)
Dim returnValue As TSource

returnValue = source.Max()

Type Parameters


The type of the elements of source.


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.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable(Of 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 Nothing.

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 Nothing, this method returns Nothing.

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

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