簡單過生活

Imports System.Threading

Public Class Form1

   Dim num As Integer

   Dim tokenSource2 As CancellationTokenSource

   Dim ct As CancellationToken

   '當按下 Run 按鈕後，建立執行緒

   Private Sub btnRUN_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRUN.Click

       num = 0

       tokenSource2 = New CancellationTokenSource()

       ct = tokenSource2.Token

       '建立執行緒，執行 run 函式

       Dim t As Threading.Tasks.Task = Threading.Tasks.Task.Factory.StartNew(AddressOf run, tokenSource2.Token)

   End Sub

   '當按下 STOP 按鈕後，將執行緒 Cancel

   Private Sub btnSTOP_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSTOP.Click

       tokenSource2.Cancel()

   End Sub

   Private Sub run()

       ct.ThrowIfCancellationRequested()

       MsgBox("執行緒開始")

       While (True)

           If ct.IsCancellationRequested Then

               '離開執行緒

               MsgBox("執行緒結束")

               Exit Sub

           End If

           num = num + 1

           '更新 UI

           SetUI(num.ToString, TextBox1)

           '停止 1 秒

           Thread.Sleep(1000)

       End While

   End Sub

   '更新 UI

   Private Delegate Sub UpdateUI(ByVal msg As String, ByVal con As Control)

   Private Sub SetUI(ByVal msg As String, ByVal con As Control)

       If Me.InvokeRequired() Then

           Dim um As New UpdateUI(AddressOf SetUI)

           Me.Invoke(um, msg, con)

       Else

           TextBox1.Text = msg

       End If

   End Sub

End Class