在VB中调用一个函数，若在指定时间内无返回值，怎么样才能强行中止它？

下面的例子测试一下：Dim bolCancel As Boolean
Private Sub Command1_Click()
    bolCancel = False
    For i = 1 To 1000000
        Me.Caption = i
        If bolCancel Then Exit Sub
        DoEvents
    Next i
End SubPrivate Sub Command2_Click()
    bolCancel = True
End Sub