.NET Framework Class Library
EnumerableLastOrDefaultTSource Method (IEnumerableTSource, FuncTSource, Boolean)

Returns the last element of a sequence that satisfies a condition or a default value if no such element is found.

Namespace:   System.Linq
Assemblies:   System.Linq (in System.Linq.dll)
  System.Core (in System.Core.dll)
Syntax
<[%$TOPIC/bb548915_en-us_VS_110_1_0_0_0_0%]> _
Public Shared Function LastOrDefault(Of TSource) ( _
	source As [%$TOPIC/bb548915_en-us_VS_110_1_0_0_0_1%](Of TSource), _
	predicate As [%$TOPIC/bb548915_en-us_VS_110_1_0_0_0_2%](Of TSource, [%$TOPIC/bb548915_en-us_VS_110_1_0_0_0_3%]) _
) As TSource
public static TSource LastOrDefault<TSource>(
	this [%$TOPIC/bb548915_en-us_VS_110_1_0_1_0_0%]<TSource> source,
	[%$TOPIC/bb548915_en-us_VS_110_1_0_1_0_1%]<TSource, [%$TOPIC/bb548915_en-us_VS_110_1_0_1_0_2%]> predicate
)
[[%$TOPIC/bb548915_en-us_VS_110_1_0_2_0_0%]]
public:
generic<typename TSource>
static TSource LastOrDefault(
	[%$TOPIC/bb548915_en-us_VS_110_1_0_2_0_1%]<TSource>^ source, 
	[%$TOPIC/bb548915_en-us_VS_110_1_0_2_0_2%]<TSource, [%$TOPIC/bb548915_en-us_VS_110_1_0_2_0_3%]>^ predicate
)
static member LastOrDefault : 
        source:[%$TOPIC/bb548915_en-us_VS_110_1_0_3_0_0%]<'TSource> * 
        predicate:[%$TOPIC/bb548915_en-us_VS_110_1_0_3_0_1%]<'TSource, [%$TOPIC/bb548915_en-us_VS_110_1_0_3_0_2%]> -> 'TSource 
JScript does not support generic types or methods.

Type Parameters

TSource

The type of the elements of source.

Parameters

source
Type: System.Collections.GenericIEnumerableTSource

An IEnumerableT to return an element from.

predicate
Type: SystemFuncTSource, Boolean

A function to test each element for a condition.

Return Value

Type: TSource
default(TSource) if the sequence is empty or if no elements pass the test in the predicate function; otherwise, the last element that passes the test in the predicate function.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerableTSource. 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).
Exceptions
ExceptionCondition
ArgumentNullException

source or predicate is .

Remarks

The default value for reference and nullable types is .

Examples

The following code example demonstrates how to use LastOrDefaultTSource(IEnumerableTSource, FuncTSource, Boolean) by passing in a predicate. In the second call to the method, there is no element in the sequence that satisfies the condition.

        ' Create an array of doubles. 
        Dim numbers() As Double = {49.6, 52.3, 51.0, 49.4, 50.2, 48.3}

        ' Get the last item whose value rounds to 50.0. 
        Dim number50 As Double = _
            numbers.LastOrDefault(Function(n) Math.Round(n) = 50.0)

        Dim output As New System.Text.StringBuilder
        output.AppendLine("The last number that rounds to 50 is " & number50)

        ' Get the last item whose value rounds to 40.0. 
        Dim number40 As Double = _
            numbers.LastOrDefault(Function(n) Math.Round(n) = 40.0)

        Dim text As String = IIf(number40 = 0.0, _
                                 "[DOES NOT EXIST]", _
                                 number40.ToString())
        output.AppendLine("The last number that rounds to 40 is " & text)

        ' Display the output.
        MsgBox(output.ToString)

        ' This code produces the following output: 
        ' 
        ' The last number that rounds to 50 is 50.2 
        ' The last number that rounds to 40 is [DOES NOT EXIST]
double[] numbers = { 49.6, 52.3, 51.0, 49.4, 50.2, 48.3 };

            double last50 = numbers.LastOrDefault(n => Math.Round(n) == 50.0);

            Console.WriteLine("The last number that rounds to 50 is {0}.", last50);

            double last40 = numbers.LastOrDefault(n => Math.Round(n) == 40.0);

            Console.WriteLine(
                "The last number that rounds to 40 is {0}.",
                last40 == 0.0 ? "<DOES NOT EXIST>" : last40.ToString());

            /*
             This code produces the following output:

             The last number that rounds to 50 is 50.2.
             The last number that rounds to 40 is <DOES NOT EXIST>.
            */
Version Information

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library