Enumerable.Max(Of TSource) Method (IEnumerable(Of TSource))
Returns the maximum value in a generic sequence.
Assembly: System.Core (in System.Core.dll)
'Declaration <ExtensionAttribute> _ Public Shared Function Max(Of TSource) ( _ source As IEnumerable(Of TSource) _ ) As TSource 'Usage Dim source As IEnumerable(Of TSource) Dim returnValue As TSource returnValue = source.Max()
Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- Type: System.Collections.Generic.IEnumerable(Of TSource)
A sequence of values to determine the maximum value of.
Return Value
Type: TSourceThe 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).| Exception | Condition |
|---|---|
| ArgumentNullException | 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 Else 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
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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.