如何跟踪多个 BackgroundworkerX.Runworkercompleted 操作
How to track multiple BackgroundworkerX.Runworkercompleted operations
我正在尝试使用单个处理程序来涵盖多个 backgroundworker 活动的结束，但找不到使用 backgroundworkercompleted 事件获取有关特定 backgroundworker 的信息的方法。
我捕捉事件的代码如下：
Private Sub BGx_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted, BackgroundWorker2.RunWorkerCompleted, BackgroundWorker3.RunWorkerCompleted, BackgroundWorker4.RunWorkerCompleted, BackgroundWorker5.RunWorkerCompleted, BackgroundWorker6.RunWorkerCompleted, BackgroundWorker7.RunWorkerCompleted, BackgroundWorker8.RunWorkerCompleted
'Do work here based on completed Backgroundworker
For BG = 1 To 8
If Not DSWorkers(BG).IsBusy Then
If DStatus(BG) = -2 Then : DStatus(BG) = -1 : End If
End If
Next
Complete()
End Sub
"Do Work Here" 部分没有任何内容，因为我不知道如何捕获并且无法找到 backgroundworkercompleted 事件 ID 的详细信息。
请提供有关如何识别特定的已完成 BackgroundWorker 的任何指示
与所有事件处理程序一样，sender 参数是对引发事件的对象的引用，因此您可以通过它访问已完成其工作的实际 BackgroundWorker。如果您需要其他数据，则将其分配给 DoWork 事件处理程序中的 e.Result 属性，然后从 e.Result 属性 中取回RunWorkerCompleted 事件处理程序。 e.Result 用于从 DoWork 事件处理程序中获取数据，就像 e.Argument 用于获取数据一样。
检查this out for some examples of using BackgroundWorker objects, including passing data out using e.Result. You might also like to checkout my own BackgroundMultiWorker class，它基本上将多个BackgroundWorker对象的功能组合到一个BackgroundMultiWorker对象中。它使用令牌标识每个任务。
编辑：
这是一个可能有助于解决此问题和您的一般任务的示例：
Imports System.ComponentModel
Imports System.Threading
Public Class Form1
Private ReadOnly resultsByWorker As New Dictionary(Of BackgroundWorker, BackgroundWorkerResult)
Private ReadOnly rng As New Random
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'The NumericUpDown is used to select the index of a BackgroundWorker to cancel.
With NumericUpDown1
.DecimalPlaces = 0
.Minimum = 0
.Maximum = 9
End With
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
'Create 10 BackgroundWorkers and run them.
For i = 1 To 10
Dim worker As New BackgroundWorker
resultsByWorker.Add(worker, New BackgroundWorkerResult)
AddHandler worker.DoWork, AddressOf workers_DoWork
AddHandler worker.RunWorkerCompleted, AddressOf workers_RunWorkerCompleted
worker.WorkerSupportsCancellation = True
worker.RunWorkerAsync()
Next
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim index = Convert.ToInt32(NumericUpDown1.Value)
Dim worker = resultsByWorker.Keys.ToArray()(index)
If worker.IsBusy Then
'Cancel the BackgroundWorker at the specified index.
worker.CancelAsync()
End If
End Sub
Private Sub workers_DoWork(sender As Object, e As DoWorkEventArgs)
Dim worker = DirectCast(sender, BackgroundWorker)
'Do work for a random number of seconds between 10 and 20.
Dim period = rng.Next(10, 20 + 1)
For i = 0 To period
If worker.CancellationPending Then
e.Cancel = True
Return
End If
'Simulate work.
Thread.Sleep(1000)
Next
'The work was completed without being cancelled.
e.Result = period
End Sub
Private Sub workers_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs)
Dim worker = DirectCast(sender, BackgroundWorker)
Dim result = resultsByWorker(worker)
If e.Cancelled Then
result.WasCancelled = True
Else
result.Result = CInt(e.Result)
End If
Dim workers = resultsByWorker.Keys.ToArray()
If Not workers.Any(Function(bgw) bgw.IsBusy) Then
'All work has completed so display the results.
Dim results As New List(Of String)
For i = 0 To workers.GetUpperBound(0)
worker = workers(i)
result = resultsByWorker(worker)
results.Add($"Worker {i} {If(result.WasCancelled, "was cancelled", $"completed {result.Result} iterations")}.")
Next
MessageBox.Show(String.Join(Environment.NewLine, results))
End If
End Sub
End Class
Public Class BackgroundWorkerResult
Public Property WasCancelled As Boolean
Public Property Result As Integer
End Class
这里是修改后的示例，使用 BackgroundMultiWorker 的单个实例链接到 BackgroundWorker class.
的多个实例
Imports System.Threading
Public Class Form1
Private WithEvents worker As New BackgroundMultiWorker With {.WorkerSupportsCancellation = True}
Private ReadOnly results(9) As BackgroundWorkerResult
Private ReadOnly rng As New Random
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'The NumericUpDown is used to select the index of a BackgroundWorker to cancel.
With NumericUpDown1
.DecimalPlaces = 0
.Minimum = 0
.Maximum = results.GetUpperBound(0)
End With
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
'Create 10 BackgroundWorkers and run them.
For i = 0 To results.GetUpperBound(0)
results(i) = New BackgroundWorkerResult
worker.RunWorkerAsync(i)
Next
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim index = Convert.ToInt32(NumericUpDown1.Value)
If worker.IsBusy(index) Then
'Cancel the BackgroundWorker at the specified index.
worker.CancelAsync(index)
End If
End Sub
Private Sub worker_DoWork(sender As Object, e As DoWorkEventArgs) Handles worker.DoWork
'Do work for a random number of seconds between 10 and 20.
Dim period = rng.Next(10, 20 + 1)
For i = 0 To period
If worker.IsCancellationPending(e.Token) Then
e.Cancel = True
Return
End If
'Simulate work.
Thread.Sleep(1000)
Next
'The work was completed without being cancelled.
e.Result = period
End Sub
Private Sub workers_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs) Handles worker.RunWorkerCompleted
Dim result = results(CInt(e.Token))
If e.Cancelled Then
result.WasCancelled = True
Else
result.Result = CInt(e.Result)
End If
If Not worker.IsBusy() Then
'All work has completed so display the results.
Dim output As New List(Of String)
For i = 0 To results.GetUpperBound(0)
result = results(i)
output.Add($"Task {i} {If(result.WasCancelled, "was cancelled", $"completed {result.Result} iterations")}.")
Next
MessageBox.Show(String.Join(Environment.NewLine, output))
End If
End Sub
End Class
Public Class BackgroundWorkerResult
Public Property WasCancelled As Boolean
Public Property Result As Integer
End Class
我正在尝试使用单个处理程序来涵盖多个 backgroundworker 活动的结束，但找不到使用 backgroundworkercompleted 事件获取有关特定 backgroundworker 的信息的方法。 我捕捉事件的代码如下：
Private Sub BGx_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted, BackgroundWorker2.RunWorkerCompleted, BackgroundWorker3.RunWorkerCompleted, BackgroundWorker4.RunWorkerCompleted, BackgroundWorker5.RunWorkerCompleted, BackgroundWorker6.RunWorkerCompleted, BackgroundWorker7.RunWorkerCompleted, BackgroundWorker8.RunWorkerCompleted
'Do work here based on completed Backgroundworker
For BG = 1 To 8
If Not DSWorkers(BG).IsBusy Then
If DStatus(BG) = -2 Then : DStatus(BG) = -1 : End If
End If
Next
Complete()
End Sub
"Do Work Here" 部分没有任何内容，因为我不知道如何捕获并且无法找到 backgroundworkercompleted 事件 ID 的详细信息。
请提供有关如何识别特定的已完成 BackgroundWorker 的任何指示
与所有事件处理程序一样，sender 参数是对引发事件的对象的引用，因此您可以通过它访问已完成其工作的实际 BackgroundWorker。如果您需要其他数据，则将其分配给 DoWork 事件处理程序中的 e.Result 属性，然后从 e.Result 属性 中取回RunWorkerCompleted 事件处理程序。 e.Result 用于从 DoWork 事件处理程序中获取数据，就像 e.Argument 用于获取数据一样。
检查this out for some examples of using BackgroundWorker objects, including passing data out using e.Result. You might also like to checkout my own BackgroundMultiWorker class，它基本上将多个BackgroundWorker对象的功能组合到一个BackgroundMultiWorker对象中。它使用令牌标识每个任务。
编辑：
这是一个可能有助于解决此问题和您的一般任务的示例：
Imports System.ComponentModel
Imports System.Threading
Public Class Form1
Private ReadOnly resultsByWorker As New Dictionary(Of BackgroundWorker, BackgroundWorkerResult)
Private ReadOnly rng As New Random
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'The NumericUpDown is used to select the index of a BackgroundWorker to cancel.
With NumericUpDown1
.DecimalPlaces = 0
.Minimum = 0
.Maximum = 9
End With
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
'Create 10 BackgroundWorkers and run them.
For i = 1 To 10
Dim worker As New BackgroundWorker
resultsByWorker.Add(worker, New BackgroundWorkerResult)
AddHandler worker.DoWork, AddressOf workers_DoWork
AddHandler worker.RunWorkerCompleted, AddressOf workers_RunWorkerCompleted
worker.WorkerSupportsCancellation = True
worker.RunWorkerAsync()
Next
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim index = Convert.ToInt32(NumericUpDown1.Value)
Dim worker = resultsByWorker.Keys.ToArray()(index)
If worker.IsBusy Then
'Cancel the BackgroundWorker at the specified index.
worker.CancelAsync()
End If
End Sub
Private Sub workers_DoWork(sender As Object, e As DoWorkEventArgs)
Dim worker = DirectCast(sender, BackgroundWorker)
'Do work for a random number of seconds between 10 and 20.
Dim period = rng.Next(10, 20 + 1)
For i = 0 To period
If worker.CancellationPending Then
e.Cancel = True
Return
End If
'Simulate work.
Thread.Sleep(1000)
Next
'The work was completed without being cancelled.
e.Result = period
End Sub
Private Sub workers_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs)
Dim worker = DirectCast(sender, BackgroundWorker)
Dim result = resultsByWorker(worker)
If e.Cancelled Then
result.WasCancelled = True
Else
result.Result = CInt(e.Result)
End If
Dim workers = resultsByWorker.Keys.ToArray()
If Not workers.Any(Function(bgw) bgw.IsBusy) Then
'All work has completed so display the results.
Dim results As New List(Of String)
For i = 0 To workers.GetUpperBound(0)
worker = workers(i)
result = resultsByWorker(worker)
results.Add($"Worker {i} {If(result.WasCancelled, "was cancelled", $"completed {result.Result} iterations")}.")
Next
MessageBox.Show(String.Join(Environment.NewLine, results))
End If
End Sub
End Class
Public Class BackgroundWorkerResult
Public Property WasCancelled As Boolean
Public Property Result As Integer
End Class
这里是修改后的示例，使用 BackgroundMultiWorker 的单个实例链接到 BackgroundWorker class.
Imports System.Threading
Public Class Form1
Private WithEvents worker As New BackgroundMultiWorker With {.WorkerSupportsCancellation = True}
Private ReadOnly results(9) As BackgroundWorkerResult
Private ReadOnly rng As New Random
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'The NumericUpDown is used to select the index of a BackgroundWorker to cancel.
With NumericUpDown1
.DecimalPlaces = 0
.Minimum = 0
.Maximum = results.GetUpperBound(0)
End With
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
'Create 10 BackgroundWorkers and run them.
For i = 0 To results.GetUpperBound(0)
results(i) = New BackgroundWorkerResult
worker.RunWorkerAsync(i)
Next
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim index = Convert.ToInt32(NumericUpDown1.Value)
If worker.IsBusy(index) Then
'Cancel the BackgroundWorker at the specified index.
worker.CancelAsync(index)
End If
End Sub
Private Sub worker_DoWork(sender As Object, e As DoWorkEventArgs) Handles worker.DoWork
'Do work for a random number of seconds between 10 and 20.
Dim period = rng.Next(10, 20 + 1)
For i = 0 To period
If worker.IsCancellationPending(e.Token) Then
e.Cancel = True
Return
End If
'Simulate work.
Thread.Sleep(1000)
Next
'The work was completed without being cancelled.
e.Result = period
End Sub
Private Sub workers_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs) Handles worker.RunWorkerCompleted
Dim result = results(CInt(e.Token))
If e.Cancelled Then
result.WasCancelled = True
Else
result.Result = CInt(e.Result)
End If
If Not worker.IsBusy() Then
'All work has completed so display the results.
Dim output As New List(Of String)
For i = 0 To results.GetUpperBound(0)
result = results(i)
output.Add($"Task {i} {If(result.WasCancelled, "was cancelled", $"completed {result.Result} iterations")}.")
Next
MessageBox.Show(String.Join(Environment.NewLine, output))
End If
End Sub
End Class
Public Class BackgroundWorkerResult
Public Property WasCancelled As Boolean
Public Property Result As Integer
End Class