在VB中實作異步調用

VB本身是不支援多線程的。但是VB中的部件有程序内及程序外的區分，是以這裡我使用程序外部件來實作異步調用。

伺服器端代碼,建立一個ActiveEXE工程,加入一個窗體，窗體中存放一個Timer控件

添加一個類子產品。代碼如下

Private WithEvents m_Timer As Timer

Public Event MyTaskResult(result As Long)

Private j As Long

Private Sub Class_Initialize()

    Set m_Timer = Form1.Timer1

End Sub

Private Sub m_Timer_Timer()

      m_Timer.Enabled = False

    Dim i As Long

    Dim r As Long

    For i = 0 To j

        r = r + i

    Next

      RaiseEvent MyTaskResult(r)

End Sub

Public Sub MyBigTask(i As Long)

    m_Timer.Enabled = True

    m_Timer.Interval = 10

    j = i

End Sub

用戶端

Private WithEvents longTask As AsyncServerTest.MyAsyncCls

Private Sub Command1_Click()

    Set longTask = New AsyncServerTest.MyAsyncCls

    longTask.MyBigTask (Text1.Text)

End Sub

Private Sub longTask_MyTaskResult(result As Long)

    Text2.Text = result

    MsgBox "long task finished"

End Sub