Private Sub btnGetStockQuote2_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles btnGetStockQuote2.Click Dim sq As New StockQuote sq.StockSymbol = cmbStocks2.SelectedItem sq.ChartControl = Chart2 t2 = New Thread(AddressOf sq.InvokeWebService) t2.Start()
'激活暂停和停止按钮 btnPauseContinue.Enabled = True btnStop.Enabled = True '激活计时器控件 Timer1.Enabled = True End Sub 按F5测试这两个图表（图7所示）。为每个图表选择一只股票，你将看到这两个图表同步显示。
Private Sub btnPauseContinue_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles btnPauseContinue.Click ' 如果线程处于睡眠和运行状态就挂起它 If t2.ThreadState = ThreadState.WaitSleepJoin _ Or t2.ThreadState = ThreadState.Running Then t2.Suspend() btnPauseContinue.Text = "Continue" Else ' 继续该线程 t2.Resume() btnPauseContinue.Text = "Pause" End If End Sub 停止线程则使用Abort()方法：
Private Sub btnStop_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles btnStop.Click Try If Not t2.ThreadState = ThreadState.Stopped Then btnPauseContinue.Enabled = False btnStop.Enabled = False t2.Abort() End If Catch ex As Exception MsgBox(ex.ToString) End Try End Sub 通过运行示例项目，你会发现自己已经能够使用多线程技术建立应用程序，使应用程序在执行后台事务的时候，仍然保持响应。尽管本文的示例使用的是Web服务，但是相同的原则也可以应用于其它类型的后台事务。例如，你可以改变这个应用程序以读取外部设备（例如温度计或血压计监视设备）的数据。
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