在Windows会话解锁后，如何防止表单位置大小发生变化？

我发现一个解决方案，并发布演示代码（XE2）作为这个问题的Delphi解决方案。

这里的答案是delphiDabbler的解决方案1的组合 。

基本上我正在注册Windows会话状态更改事件（ WM_WTSSESSION_CHANGE ）。 在提供的示例中（基于裸VCL表单应用程序），我使用WM_EXITSIZEPOS消息来保存当前的表单sizepos。

Windows在位置更改消息被触发的时刻显示出不同的行为。 这就是为什么我必须修改我的初稿，现在使用两个变量。 我正在阻止会话锁定时的位置更改，并阻止会话解锁后的第一个位置更改。 位置更改是使用WM_WINDOWPOSCHANGING消息拦截的。

但是为了不恢复正常的位置，如果窗体是最大化我正在使用FRestoreNormalRect字段。

 unit Unit1; interface uses Winapi.Windows, Winapi.Messages, Vcl.Forms; type TForm1 = class(TForm) private FSessionIsLocked: Boolean; FSessionWasUnlocked: Boolean; FRestoreNormalRect: Boolean; FLeft: Integer; FTop: Integer; FWidth: Integer; FHeight: Integer; procedure WMWTSSessionChange(var Msg: TMessage); message WM_WTSSESSION_CHANGE; protected procedure CreateWnd; override; procedure DestroyWnd; override; procedure WMExitSizeMove(var Msg: TMessage); message WM_EXITSIZEMOVE; procedure WMPosChanging(var Msg: TWmWindowPosChanging); message WM_WINDOWPOSCHANGING; procedure WMSize(var Msg: TWMSize); message WM_SIZE; end; var Form1: TForm1; implementation {$R *.dfm} //-------------------------------------------------------------------------------------------------- procedure TForm1.CreateWnd; begin inherited; WTSRegisterSessionNotification(WindowHandle, NOTIFY_FOR_THIS_SESSION); end; //-------------------------------------------------------------------------------------------------- procedure TForm1.DestroyWnd; begin WTSUnRegisterSessionNotification(WindowHandle); inherited; end; //-------------------------------------------------------------------------------------------------- procedure TForm1.WMExitSizeMove(var Msg: TMessage); var WP: TWindowPlacement; NormalRect: TRect; begin WP.Length := SizeOf(TWindowPlacement); GetWindowPlacement(Self.Handle, @WP); NormalRect := WP.rcNormalPosition; FLeft := NormalRect.Left; FTop := NormalRect.Top; FWidth := NormalRect.Right - NormalRect.Left; FHeight := NormalRect.Bottom - NormalRect.Top; end; //-------------------------------------------------------------------------------------------------- procedure TForm1.WMPosChanging(var Msg: TWmWindowPosChanging); begin { Sizepos changes might occur due to locks or unlocks. We need do prohibit both. While the session is locked we ignore all position changes. When the session has been unlocked we will ignore the next PosChanging message. } if FSessionIsLocked or FSessionWasUnlocked then begin { overwrite with the old settings } if FRestoreNormalRect then begin Msg.WindowPos.x := FLeft; Msg.WindowPos.y := FTop; Msg.WindowPos.cx := FWidth; Msg.WindowPos.cy := FHeight; Msg.Result := 0; end; { reset the variable, otherwise a manual resize would not be possible } if FSessionWasUnlocked then FSessionWasUnlocked := False; end; end; //-------------------------------------------------------------------------------------------------- procedure TiQForm.WMSize(var Msg: TWMSize); begin inherited; { We need to restore our normal rect only if the form is not maximized. Because if it is maximized it only positioned on one monitor and will not be moved by windows. If we do not repsect this case we would be restoring the normal rect unintentionally in WMPosChanging for every maximized form. } FRestoreNormalRect := not (Msg.SizeType = SIZE_MAXIMIZED); end; //-------------------------------------------------------------------------------------------------- procedure TForm1.WMWTSSessionChange(var Msg: TMessage); begin case Message.WParam of WTS_CONSOLE_DISCONNECT, WTS_REMOTE_DISCONNECT, WTS_SESSION_LOCK, WTS_SESSION_LOGOFF: begin FSessionIsLocked := True; end; WTS_CONSOLE_CONNECT, WTS_REMOTE_CONNECT, WTS_SESSION_UNLOCK, WTS_SESSION_LOGON: begin FSessionIsLocked := False; FSessionWasUnlocked := True; end; end; inherited; end; //-------------------------------------------------------------------------------------------------- end.