' 导入命名空间
Imports System.Collections.Generic
Imports System.Threading
Imports System.Threading.Tasks

Module Example
   Public Sub Main()
      Dim cts As New CancellationTokenSource()
      Dim token As CancellationToken = cts.Token
      Dim tasks As New List(Of Task)()
      Dim rnd As New Random()
      Dim lockObj As New Object()
      Dim words6() As String = { "reason", "editor", "rioter", "rental",
                                 "senior", "regain", "ordain", "rained" }

      For Each word6 in words6
         tasks.Add(Task.Factory.StartNew( Sub(word)
                                              Dim chars() As Char = word.ToString().ToCharArray()
                                              Dim order(chars.Length - 1) As Double
                                              Dim wasZero As Boolean = False
                                              SyncLock lockObj
                                                 For ctr As Integer = 0 To order.Length - 1
                                                    order(ctr) = rnd.NextDouble()
                                                    If order(ctr) = 0 Then
                                                       If Not wasZero Then
                                                          wasZero = True
                                                       Else
                                                          cts.Cancel()
                                                       End If
                                                    End If
                                                 Next
                                              End SyncLock
                                              token.ThrowIfCancellationRequested()
                                              Array.Sort(order, chars)
                                              Console.WriteLine("{0} --> {1}", word,
                                                                new String(chars))
                                          End Sub, word6))
      Next
      Try
         Task.WaitAll(tasks.ToArray())
      Catch e As AggregateException
         For Each ie In e.InnerExceptions
            If TypeOf ie Is OperationCanceledException
               Console.WriteLine("The word scrambling operation has been cancelled.")
               Exit For
            Else
               Console.WriteLine(ie.GetType().Name + ": " + ie.Message)
            End If
         Next
      Finally
         cts.Dispose()
      End Try
   End Sub
End Module

' 导入命名空间
Imports System.Collections.Generic
Imports System.IO
Imports System.Threading
Imports System.Threading.Tasks

Module Example
   Public Sub Main()
      Dim tokenSource As New CancellationTokenSource()
      Dim token As CancellationToken = tokenSource.Token
      Dim files As New List(Of Tuple(Of String, String, Long, Date))()

      Dim t As Task = Task.Factory.StartNew( Sub()
                                   Dim dir As String = "C:\Windows\System32\"
                                   Dim obj As New Object()
                                   If Directory.Exists(dir)Then
                                      Parallel.ForEach(Directory.GetFiles(dir), 
                                         Sub(f)
                                            If token.IsCancellationRequested Then
                                               token.ThrowIfCancellationRequested()
                                            End If  
                                            Dim fi As New FileInfo(f)
                                            SyncLock(obj)
                                              files.Add(Tuple.Create(fi.Name, fi.DirectoryName, fi.Length, fi.LastWriteTimeUtc))          
                                            End SyncLock
                                         End Sub)
                                   End If
                                End Sub, token)
      tokenSource.Cancel()
      Try
         t.Wait() 
         Console.WriteLine("Retrieved information for {0} files.", files.Count)
      Catch e As AggregateException
         Console.WriteLine("Exception messages:")
         For Each ie As Exception In e.InnerExceptions
            Console.WriteLine("   {0}:{1}", ie.GetType().Name, ie.Message)
         Next
         Console.WriteLine()
         Console.WriteLine("Task status: {0}", t.Status)       
      Finally
         tokenSource.Dispose()
      End Try
   End Sub
End Module

' 导入命名空间
Imports System.Collections.Generic
Imports System.Threading.Tasks

Public Module Example
   Public Sub Main()
      Dim rnd As New Random()
      Dim tasks As New List(Of Task)
      ' Execute the task 10 times.
      For ctr As Integer = 1 To 9
         tasks.Add(Task.Factory.StartNew(Sub()
                                            Dim utf32 As Integer
                                            SyncLock(rnd)
                                               ' Get UTF32 value.
                                               utf32 = rnd.Next(0, &hE01F0)
                                            End SyncLock
                                            ' Convert it to a UTF16-encoded character.
                                            Dim utf16 As String = Char.ConvertFromUtf32(utf32)
                                            ' Display information about the character.
                                            Console.WriteLine("0x{0:X8} --> '{1,2}' ({2})", 
                                                              utf32, utf16, ShowHex(utf16))
                                         End Sub))                           
      Next
      Task.WaitAll(tasks.ToArray()) 
   End Sub
   
   Private Function ShowHex(value As String) As String
      Dim hexString As String = Nothing
      ' Handle only non-control characters.
      If Not Char.IsControl(value, 0) Then
         For Each ch In value
            hexString += String.Format("0x{0} ", Convert.ToUInt16(ch))
         Next
      End If   
      Return hexString.Trim()
   End Function
End Module