如何向windows投递暂停关机消息

Question

  有些系统程序需要在关闭windows之前执行数据保存后退出，怎么做到呢？获取windows消息容易，但是如何向windows投递一条暂停关机的消息，直到应用系统完成退出操作，再投递一条继续关机的消息？

Answer 1

你可以使窗体类继承Control.WndProc，然后响应WM_QUERYENDSESSION事件，比如

'constants needed, form level
Private Const WM_QUERYENDSESSION As System.Int32 = &H11
Private Const WM_CANCELMODE As System.Int32 = &H1F

'the sub to intercept the windows messages
Protected Overrides Sub WndProc(ByRef ex As Message)
  If ex.Msg = WM_QUERYENDSESSION Then
    'cancel the message
    Dim MyMsg As New Message
    MyMsg.Msg = WM_CANCELMODE
    MyBase.WndProc(MyMsg)
  Else
    'send the message as normal
    MyBase.WndProc(ex)
  End If
End Sub 

Answer 2

你可以使窗体类继承Control.WndProc，然后响应WM_QUERYENDSESSION事件，比如

 

'constants needed, form level

Private Const WM_QUERYENDSESSION As System.Int32 = &H11

Private Const WM_CANCELMODE As System.Int32 = &H1F



'the sub to intercept the windows messages

Protected Overrides Sub WndProc(ByRef ex As Message)

 If ex.Msg = WM_QUERYENDSESSION Then

  'cancel the message

  Dim MyMsg As New Message

  MyMsg.Msg = WM_CANCELMODE

  MyBase.WndProc(MyMsg)

 Else

  'send the message as normal

  MyBase.WndProc(ex)

 End If

End Sub 

 

vb的代码.........

Answer 3

//constants needed, form level
private const System.Int32 WM_QUERYENDSESSION = 0x11;

private const System.Int32 WM_CANCELMODE = 0x1f;
//the sub to intercept the windows messages
protected override void WndProc(ref Message ex)
{
  if (ex.Msg == WM_QUERYENDSESSION)
  {
    //cancel the message
    Message MyMsg = new Message();
    MyMsg.Msg = WM_CANCELMODE;
    base.WndProc(MyMsg);
  }
  else
  {
    //send the message as normal
    base.WndProc(ex);
  }
}

---

小中中的學習筆記

Answer 4

//constants needed, form level

private const System.Int32 WM_QUERYENDSESSION = 0x11;



private const System.Int32 WM_CANCELMODE = 0x1f;

//the sub to intercept the windows messages

protected override void WndProc(ref Message ex)

{

 if (ex.Msg == WM_QUERYENDSESSION)

 {

 //cancel the message

 Message MyMsg = new Message();

 MyMsg.Msg = WM_CANCELMODE;

 base.WndProc(MyMsg);

 }

 else

 {

 //send the message as normal

 base.WndProc(ex);

 }

}

---

小中中的學習筆記

//constants needed, form level

private const System.Int32 WM_QUERYENDSESSION = 0x11;



private const System.Int32 WM_CANCELMODE = 0x1f;

//the sub to intercept the windows messages

protected override void WndProc(ref Message ex)

{

  if (ex.Msg == WM_QUERYENDSESSION)

  {

    //cancel the message

    Message MyMsg = new Message();

    MyMsg.Msg = WM_CANCELMODE;

    base.WndProc(ref MyMsg);

  }

  else

  {

    //send the message as normal

    base.WndProc(ref ex);

  }

}

vs2008要修改下就可以了