Activated事件对MDI子窗体不起作用.如果您要捕获MDI子窗体的激活事件,您需要在父窗体的MdiChildActivate事件中编写代码,例如:
Private Sub Form1_MdiChildActivate(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.MdiChildActivate
Dim f As Form = Me.ActiveMdiChild
Select Case f.Name
Case "Child1"
'Do something...
Case "Child2"
'Do something...
End Select
End Sub