vb System.Func<T1,T2,T3,T4,TResult>类(方法)实例源码

' 导入命名空间
Imports System.Collections.Generic
Imports System.Linq

Public Module Func3Example

   Public Sub Main()
      Dim predicate As Func(Of String, Integer, Boolean) = Function(str, index) str.Length = index

      Dim words() As String = { "orange", "apple", "Article", "elephant", "star", "and" }
      Dim aWords As IEnumerable(Of String) = words.Where(predicate)

      For Each word As String In aWords
         Console.WriteLine(word)
      Next   
   End Sub
End Module

Delegate Function Searcher(searchString As String, _
                           start As Integer,  _
                           count As Integer, _
                           type As StringComparison) As Integer

Module DelegateExample
   Public Sub Main()
      Dim title As String = "The House of the Seven Gables"
      Dim position As Integer = 0
      Dim finder As Searcher = AddressOf title.IndexOf
      Do
         Dim characters As Integer = title.Length - position
         position = finder("the", position, characters, _
                         StringComparison.InvariantCultureIgnoreCase) 
         If position >= 0 Then
            position += 1
            Console.WriteLine("'The' found at position {0} in {1}.", _
                              position, title)
         End If   
      Loop While position > 0   
   End Sub
End Module

Module DelegateExample
   Public Sub Main()
      Dim title As String = "The House of the Seven Gables"
      Dim position As Integer = 0
      Dim finder As Func(Of String, Integer, Integer, StringComparison, Integer) _
                    = AddressOf title.IndexOf
      Do
         Dim characters As Integer = title.Length - position
         position = finder("the", position, characters, _
                         StringComparison.InvariantCultureIgnoreCase) 
         If position >= 0 Then
            position += 1
            Console.WriteLine("'The' found at position {0} in {1}.", _
                              position, title)
         End If   
      Loop While position > 0   
   End Sub
End Module

Module DelegateExample
   Public Sub Main()
      Dim title As String = "The House of the Seven Gables"
      Dim position As Integer = 0
      Dim finder As Func(Of String, Integer, Integer, StringComparison, Integer) _
                    = Function(s, pos, chars, type) _
                    title.IndexOf(s, pos, chars, type)
      Do
         Dim characters As Integer = title.Length - position
         position = finder("the", position, characters, _
                         StringComparison.InvariantCultureIgnoreCase) 
         If position >= 0 Then
            position += 1
            Console.WriteLine("'The' found at position {0} in {1}.", _
                              position, title)
         End If   
      Loop While position > 0   
   End Sub
End Module