在VB中实现异步调用

VB本身是不支持多线程的。但是VB中的部件有进程内及进程外的区分，因此这里我使用进程外部件来实现异步调用。

服务器端代码,新建一个ActiveEXE工程,加入一个窗体，窗体中存放一个Timer控件

添加一个类模块。代码如下

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

客户端

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