Enumerable.Max<TSource> Method (IEnumerable<TSource>, Func<TSource, Int32>)
Invokes a transform function on each element of a sequence and returns the maximum Int32 value.
Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
public static int Max<TSource>( this IEnumerable<TSource> source, Func<TSource, int> selector )
Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- Type: System.Collections.Generic.IEnumerable<TSource>
A sequence of values to determine the maximum value of.
- selector
- Type: System.Func<TSource, Int32>
A transform function to apply to each element.
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).| Exception | Condition |
|---|---|
| ArgumentNullException | source or selector is null. |
| InvalidOperationException | source contains no elements. |
The Max<TSource>(IEnumerable<TSource>, Func<TSource, Int32>) method uses the Int32 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 Int32.
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.
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);
Console.WriteLine(
"The maximum pet age plus name length is {0}.",
max);
}
/*
This code produces the following output:
The maximum pet age plus name length is 14.
*/
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
