vb.net下的窗体卸载事件不在使用Unload了，改用Closed，具体的写法如下：

Private Sub Form1_FormClosing(ByVal sender As Object,ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
Dim isDataSavad As MsgBoxResult
isDataSavad = MsgBox("您确定要退出该系统吗？",vbYesNo + vbQuestion,"提示")

If isDataSavad = vbNo Then
e.Cancel = True
Else
e.Cancel = False
End If
End Sub

看似很简单，除了方法名变了其它的几乎没有变化...