窗体关闭的原因

VB6中有个Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)的方法可以捕获窗体关闭时间，查了一下ＭＳＤＮ，UnloadMode有几个枚举值：

Constant	Value	Description
vbFormControlMenu	0	The user chose the Close command from the Control menu on the form.
vbFormCode	1	The Unload statement is invoked from code.
vbAppWindows	2	The current Microsoft Windows operating environment session is ending.
vbAppTaskManager	3	The Microsoft Windows Task Manager is closing the application.
vbFormMDIForm	4	An MDI child form is closing because the MDI form is closing.
vbFormOwner	5	A form is closing because its owner is closing.

使用如下简单代码：
Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)
    Select Case UnloadMode
        Case vbFormControlMenu   
     　 MsgBox　"vbFormControlMenu"
        Case vbFormCode
        MsgBox "vbFormCode"
        Case vbAppWindows
        MsgBox "vbAppWindows"             
    End Select
End Sub
Ｃａｎｅｌ的值要是０就可以关闭，要是其他值，关闭无效，不明白干嘛不直接设Ｃａｎｃｅｌ为布尔变量。
但是也就能试试几个原因
在．ＮＥＴ下，这种捕获升级到CloseReason这个变量，如下
Private Sub Form_closing(ByVal sender As Object, ByVal e As Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        Select Case e.CloseReason
            Case CloseReason.UserClosing
                MsgBox("Close form use X")
            Case CloseReason.FormOwnerClosing
                MsgBox("Close form inner")
            Case CloseReason.None
                MsgBox("unkown reason")
            Case CloseReason.TaskManagerClosing
                If MsgBox("The task manager do", MsgBoxStyle.YesNo, Me.Text) = MsgBoxResult.No Then
                    e.Cancel = 1
                End If
            Case CloseReason.ApplicationExitCall
                MsgBox("Out")
        End Select
    End Sub
比较简单，以前不知道，记录下来．．．