VB.Net/LINQ/Lambda

Lambda expression syntax

  
Option Strict On
Imports System.Collections.Generic
Module Program
  Sub Main()
    Dim list As New List(Of Integer)()
    list.AddRange(New Integer() {20, 1, 4, 8, 9, 44})
    Dim evenNumbers As List(Of Integer) = list.FindAll(Function(i As Integer) (i Mod 2) = 0)
    For Each evenNumber As Integer In evenNumbers
      Console.WriteLine(evenNumber)
    Next
  End Sub
  Function IsEvenNumber(ByVal i As Integer) As Boolean
    Return (i Mod 2) = 0
  End Function
  Sub LambdaExpressionSyntax()
  End Sub
End Module

Lambdas with Multiple Params

  

Option Strict On
Public Delegate Function BinaryOp(ByVal x As Integer, ByVal y As Integer) As Integer
Public Class SimpleMath
  Public Function Add(ByVal x As Integer, ByVal y As Integer) As Integer
    Return x + y
  End Function
  Public Function Subtract(ByVal x As Integer, _
    ByVal y As Integer) As Integer
    Return x - y
  End Function
End Class
Module Program
  Sub Main()
    Dim b As New BinaryOp(Function(x, y) x + y)
    DisplayDelegateInfo(b)
    Console.WriteLine(b(10, 10))
  End Sub
  Sub DisplayDelegateInfo(ByVal delObj As System.Delegate)
    For Each d As System.Delegate In delObj.GetInvocationList()
      Console.WriteLine("Method Name: {0}", d.Method)
      Console.WriteLine("Type Name: {0}", d.Target)
    Next
  End Sub
End Module

Lambda with No Args

  
Option Strict On
Public Delegate Function GetTime() As String
Module Test
  Sub Main()
    Dim t As New GetTime(Function() DateTime.Now.ToString())
    Console.WriteLine(t)
  End Sub
End Module

LINQ query with Enumerable / Lambdas

  

Module Program
  Sub Main()
    Dim currentVideoGames() As String = {"A", "B", "this is a test", "C", "D", "E"}

    Dim subset = Enumerable.Where(currentVideoGames, Function(game) game.Length > 6).OrderBy(Function(game) game).Select(Function(game) game)
    For Each game In subset
      Console.WriteLine("Item: {0}", game)
    Next

  End Sub

End Module