FTP | CCD | Buscar | Trucos | Trabajo | Foros |
#1
|
||||
|
||||
Scroll Bars
Saludos a todos los amigos del foro.
Mi problema es el siguiente: Con D6 en una aplicación MDI, ¿Cómo puedo evitar que salgan los scrollbars en el mdiForm, cuando alguna de las mdiChilds sale fuera de los límites del mdiForm?. En el evento OnCreate de la mdiForm tengo preseteadas las siguientes propiedades: VertScrollBar.visible:=False; HorzScrollBar.visible:=False; AutoScroll:=False; Saludos desde Cádiz |
#2
|
||||
|
||||
Navegando por la red he encontrado la solución.
La he probado y funciona. Aquí os dejo la solución por si a alguien le interesa. Sobre la siguiente explicación hay un detalle en el que no la he seguido al pie de la letra, en la parte donde se debia de poner en el evento OnCreate, yo lo he puesto en el OnActivate (ClientHandle en Oncreate no se inicializa) *************************************************** > Is there a way to turn off the scrollbars in an MDIForm?. Yes, but you should not use it. But if you are determined: here is an older post on the subject. > How can I hide scrollbars on a MDI Form ? > I tried to set the properties AutoScroll, HorzScrollBar.Visible, > VertScrollBar.visible to false but it had no effect. this has no effect since the scrollbars do not belong to the MDI frame window itself, they belong to the client window, which is not a Delphi form. Which means one has to attack the problem on the API level. Since this question has come up so frequently in recent days i have modified a sample based on the stock MDI project to include this feature. The salient parts are quoted below. Open the main forms unit in the IDE. If you don't have a handler for the OnCreate event, add one. In the handler you do this: If ClientHandle <> 0 Then Begin If GetWindowLong( ClientHandle, GWL_USERDATA ) <> 0 Then Exit; // cannot subclass client window, userdata already in use SetWindowLong( ClientHandle, GWL_USERDATA, SetWindowLong( ClientHandle, GWL_WNDPROC, integer( @ClientWindowProc))); End; Add a new standalone function to the unit, it has to go above the FormCreate method since it is referenced in the statement above. Function ClientWindowProc( wnd: HWND; msg: Cardinal; wparam, lparam: Integer ): Integer; stdcall; Var f: Pointer; Begin f:= Pointer( GetWindowLong( wnd, GWL_USERDATA )); Case msg of WM_NCCALCSIZE: Begin If ( GetWindowLong( wnd, GWL_STYLE ) and (WS_HSCROLL or WS_VSCROLL)) <> 0 Then SetWindowLong( wnd, GWL_STYLE, GetWindowLong( wnd, GWL_STYLE ) and not (WS_HSCROLL or WS_VSCROLL)); End; End; Result := CallWindowProc( f, wnd, msg, wparam, lparam ); End; I clipped this code from a larger project, so lets hope i did not create errors in the process. What this code does is to subclass the client window the API way. It stores the old window function into the GWL_USERDATA field of the window structure since it is needed in the replacement window function, all messages need to be passed on to the old window function. There is only one message of interest in this case (the use of a Case results from the larger project, which handles more than this message): WM_NCCALCSIZE. The window gets this message when Windows tries to hide or show the scrollbars, among other cases. And it arrives *before* there is any painting of the scrollbar. So we can check if the window is going to sprout scrollbars and simply remove the scrollbar styles again. For the purists: there is no need to undo the subclassing before the form is destroyed since the client window is destroyed before the form object. ************************************************** Saludos desde cai |
|
|
Temas Similares | ||||
Tema | Autor | Foro | Respuestas | Último mensaje |
Las horrorosas scroll bars | elcigarra | OOP | 5 | 16-08-2005 20:42:05 |
ListBox - Scroll | Kreyser | Varios | 2 | 08-06-2005 13:27:24 |
Scroll en un listbox | kakesoft | OOP | 0 | 06-04-2005 02:40:25 |
Scroll en un reporte | buitrago_listas | Impresión | 0 | 19-01-2005 15:39:24 |
DBGRID y SCROLL | vtdeleon | OOP | 2 | 22-12-2004 14:34:59 |
|