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VB.NET Task类代码示例

本文整理汇总了VB.NET中System.Threading.Tasks.Task的典型用法代码示例。如果您正苦于以下问题:VB.NET Task类的具体用法?VB.NET Task怎么用?VB.NET Task使用的例子?那么, 这里精选的类代码示例或许可以为您提供帮助。


在下文中一共展示了Task类的8个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的VB.NET代码示例。

示例1: Example

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

Module Example
    Public Sub Main()
        Dim action As Action(Of Object) = 
              Sub(obj As Object)
                 Console.WriteLine("Task={0}, obj={1}, Thread={2}", 
                 Task.CurrentId, obj,
                 Thread.CurrentThread.ManagedThreadId)
              End Sub

        ' Construct an unstarted task
        Dim t1 As New Task(action, "alpha")

        ' Construct a started task
        Dim t2 As Task = Task.Factory.StartNew(action, "beta")
        ' Block the main thread to demonstrate that t2 is executing
        t2.Wait()

        ' Launch t1 
        t1.Start()
        Console.WriteLine("t1 has been launched. (Main Thread={0})",
                          Thread.CurrentThread.ManagedThreadId)
        ' Wait for the task to finish.
        t1.Wait()

        ' Construct a started task using Task.Run.
        Dim taskData As String = "delta"
        Dim t3 As Task = Task.Run(Sub()
                                     Console.WriteLine("Task={0}, obj={1}, Thread={2}",
                                     Task.CurrentId, taskData,
                                     Thread.CurrentThread.ManagedThreadId)
                                  End Sub)
        ' Wait for the task to finish.
        t3.Wait()
        
        ' Construct an unstarted task
        Dim t4 As New Task(action, "gamma")
        ' Run it synchronously
        t4.RunSynchronously()
        ' Although the task was run synchronously, it is a good practice
        ' to wait for it in the event exceptions were thrown by the task.
        t4.Wait()
    End Sub
End Module
开发者ID:VB.NET开发者,项目名称:System.Threading.Tasks,代码行数:47,代码来源:Task

输出:

Task=1, obj=beta, Thread=3
t1 has been launched. (Main Thread=1)
Task=2, obj=alpha, Thread=3
Task=3, obj=delta, Thread=3
Task=4, obj=gamma, Thread=1

示例2: Example

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

Module Example
   Public Sub Main()
      Dim t As Task = Task.Run(Sub()
                                  ' Just loop.
                                  Dim ctr As Integer = 0
                                  For ctr = 0 to 1000000
                                  Next
                                  Console.WriteLine("Finished {0} loop iterations",
                                                    ctr)
                               End Sub)
      t.Wait()
   End Sub
End Module
开发者ID:VB.NET开发者,项目名称:System.Threading.Tasks,代码行数:16,代码来源:Task

输出:

Finished 1000001 loop iterations

示例3: Example

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

Module Example
   Public Sub Main()
      Dim t As Task = Task.Factory.StartNew(Sub()
                                  ' Just loop.
                                  Dim ctr As Integer = 0
                                  For ctr = 0 to 1000000
                                  Next
                                  Console.WriteLine("Finished {0} loop iterations",
                                                    ctr)
                               End Sub)
      t.Wait()
   End Sub
End Module
开发者ID:VB.NET开发者,项目名称:System.Threading.Tasks,代码行数:16,代码来源:Task

输出:

Finished 1000001 loop iterations

示例4: Example

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

Module Example
   Public Sub Main()
      ' Wait on a single task with no timeout specified.
      Dim taskA = Task.Run( Sub() Thread.Sleep(2000))
      Console.WriteLine("taskA Status: {0}", taskA.Status)
      Try
        taskA.Wait()
        Console.WriteLine("taskA Status: {0}", taskA.Status)
      Catch e As AggregateException
         Console.WriteLine("Exception in taskA.")
      End Try
   End Sub
End Module
开发者ID:VB.NET开发者,项目名称:System.Threading.Tasks,代码行数:17,代码来源:Task

输出:

taskA Status: WaitingToRun
taskA Status: RanToCompletion

示例5: Example

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

Module Example
   Public Sub Main()
      ' Wait on a single task with a timeout specified.
      Dim taskA As Task = Task.Run( Sub() Thread.Sleep(2000))
      Try
         taskA.Wait(1000)        ' Wait for 1 second.
         Dim completed As Boolean = taskA.IsCompleted
         Console.WriteLine("Task.Completed: {0}, Status: {1}",
                           completed, taskA.Status)
         If Not completed Then 
            Console.WriteLine("Timed out before task A completed.")
         End If                     
      Catch e As AggregateException
         Console.WriteLine("Exception in taskA.")
      End Try
   End Sub
End Module
开发者ID:VB.NET开发者,项目名称:System.Threading.Tasks,代码行数:21,代码来源:Task

输出:

Task A completed: False, Status: Running
Timed out before task A completed.

示例6: Example

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

Module Example
   Public Sub Main()
      Dim tasks(2) As Task
      Dim rnd As New Random()
      For ctr As Integer = 0 To 2
         tasks(ctr) = Task.Run( Sub()  Thread.Sleep(rnd.Next(500, 3000)))
      Next
      
      Try 
         Dim index As Integer= Task.WaitAny(tasks)
         Console.WriteLine("Task #{0} completed first.", tasks(index).Id)
         Console.WriteLine()
         Console.WriteLine("Status of all tasks:")
         For Each t in tasks
            Console.WriteLine("   Task #{0}: {1}", t.Id, t.Status)
         Next   
      Catch e As AggregateException
         Console.WriteLine("An exception occurred.")
      End Try
   End Sub
End Module
开发者ID:VB.NET开发者,项目名称:System.Threading.Tasks,代码行数:25,代码来源:Task

输出:

Task #1 completed first.

Status of all tasks:
Task #3: Running
Task #1: RanToCompletion
Task #4: Running

示例7: Example

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

Module Example
   Public Sub Main()
      ' Wait for all tasks to complete.
      Dim tasks(9) As Task
      For i As Integer = 0 To 9
          tasks(i) = Task.Run( Sub() Thread.Sleep(2000) )
      Next
      Try 
         Task.WaitAll(tasks)
      Catch ae As AggregateException
         Console.WriteLine("One or more exceptions occurred: ")
         For Each ex In ae.Flatten().InnerExceptions
            Console.WriteLine("   {0}", ex.Message)
         Next
      End Try   

      Console.WriteLine("Status of completed tasks:")
      For Each t in tasks
         Console.WriteLine("   Task #{0}: {1}", t.Id, t.Status)
      Next   
   End Sub
End Module
开发者ID:VB.NET开发者,项目名称:System.Threading.Tasks,代码行数:26,代码来源:Task

输出:

Status of completed tasks:
Task #2: RanToCompletion
Task #1: RanToCompletion
Task #3: RanToCompletion
Task #4: RanToCompletion
Task #6: RanToCompletion
Task #5: RanToCompletion
Task #7: RanToCompletion
Task #8: RanToCompletion
Task #9: RanToCompletion
Task #10: RanToCompletion

示例8: Example

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

Module Example
   Public Sub Main()
      ' Create a cancellation token and cancel it.
      Dim source1 As New CancellationTokenSource()
      Dim token1 As CancellationToken = source1.Token
      source1.Cancel()
      ' Create a cancellation token for later cancellation.
      Dim source2 As New CancellationTokenSource()
      Dim token2 As CancellationToken = source2.Token
       
      ' Create a series of tasks that will complete, be cancelled, 
      ' timeout, or throw an exception.
      Dim tasks(11) As Task
      For i As Integer = 0 To 11
          Select Case i Mod 4 
             ' Task should run to completion.
             Case 0
                tasks(i) = Task.Run( Sub() Thread.Sleep(2000))
             ' Task should be set to canceled state.
             Case 1   
                tasks(i) = Task.Run( Sub() Thread.Sleep(2000), token1)
             Case 2
                ' Task should throw an exception.
                tasks(i) = Task.Run( Sub() 
                                        Throw New NotSupportedException() 
                                     End Sub)
             Case 3
                ' Task should examine cancellation token.
                tasks(i) = Task.Run( Sub() 
                                        Thread.Sleep(2000) 
                                        If token2.IsCancellationRequested
                                           token2.ThrowIfCancellationRequested()
                                        End If
                                        Thread.Sleep(500) 
                                     End Sub, token2)   
          End Select
      Next
      Thread.Sleep(250)
      source2.Cancel()
       
      Try 
         Task.WaitAll(tasks)
      Catch ae As AggregateException
         Console.WriteLine("One or more exceptions occurred:")
         For Each ex in ae.InnerExceptions
             Console.WriteLine("   {0}: {1}", ex.GetType().Name, ex.Message)
         Next
      End Try   
      Console.WriteLine()
      
      Console.WriteLine("Status of tasks:")
      For Each t in tasks
         Console.WriteLine("   Task #{0}: {1}", t.Id, t.Status)
         If t.Exception IsNot Nothing Then
            For Each ex in t.Exception.InnerExceptions
               Console.WriteLine("      {0}: {1}", ex.GetType().Name,
                                 ex.Message)
            Next
         End If
      Next
   End Sub
End Module
开发者ID:VB.NET开发者,项目名称:System.Threading.Tasks,代码行数:66,代码来源:Task

输出:

One or more exceptions occurred:
TaskCanceledException: A task was canceled.
NotSupportedException: Specified method is not supported.
TaskCanceledException: A task was canceled.
TaskCanceledException: A task was canceled.
NotSupportedException: Specified method is not supported.
TaskCanceledException: A task was canceled.
TaskCanceledException: A task was canceled.
NotSupportedException: Specified method is not supported.
TaskCanceledException: A task was canceled.

Status of tasks:
Task #13: RanToCompletion
Task #1: Canceled
Task #3: Faulted
NotSupportedException: Specified method is not supported.
Task #8: Canceled
Task #14: RanToCompletion
Task #4: Canceled
Task #6: Faulted
NotSupportedException: Specified method is not supported.
Task #7: Canceled
Task #15: RanToCompletion
Task #9: Canceled
Task #11: Faulted
NotSupportedException: Specified method is not supported.
Task #12: Canceled


注:本文中的System.Threading.Tasks.Task类示例由纯净天空整理自Github/MSDocs等开源代码及文档管理平台,相关代码片段筛选自各路编程大神贡献的开源项目,源码版权归原作者所有,传播和使用请参考对应项目的License;未经允许,请勿转载。