我正在尝试在 VCL Forms 应用程序中同步两个 TDBGrid 组件的滚动,我在拦截每个网格组件的 WndProc 时遇到了困难,而没有一些堆栈问题。我曾尝试在滚动事件下发送 WM_VSCROLL 消息,但这仍然会导致操作不正确。它需要用于单击滚动条、突出显示单元格或向上或向下鼠标按钮。整个想法是让两个彼此相邻的网格显示一种匹配的对话框。
试过了
SendMessage( gridX.Handle, WM_VSCROLL, SB_LINEDOWN, 0 );
还
procedure TForm1.GridXCustomWndProc( var Msg: TMessage );
begin
Msg.Result := CallWindowProc( POldWndProc, gridX.Handle, Msg.Msg, Msg.wParam, Msg.lParam );
if ( Msg.Msg = WM_VSCROLL ) then
begin
gridY.SetActiveRow( gridX.GetActiveRow );
gridY.Perform( Msg.Msg, Msg.wParam, Msg.lParam );
SetScrollPos( gridY.Handle, SB_VERT, HIWORD( Msg.wParam ), True );
end;
end;
和
procedure TForm1.GridxCustomWndProc( var Msg: TMessage );
begin
if ( Msg.Msg = WM_VSCROLL ) then
begin
gridY.SetActiveRow( gridX.GetActiveRow );
gridY.Perform( Msg.Msg, Msg.wParam, Msg.lParam );
SetScrollPos( gridY.Handle, SB_VERT, HIWORD( Msg.wParam ), True );
end;
inherited WndProc( Msg );
end;
第一个只是临时解决方案,第二个导致无效的内存读取,第三个导致堆栈溢出。所以这些解决方案似乎都不适合我。我很想就如何完成这项任务提供一些意见!提前致谢。
更新:解决方案
private
[...]
GridXWndProc, GridXSaveWndProc: Pointer;
GridYWndProc, GridYSaveWndProc: Pointer;
procedure GridXCustomWndProc( var Msg: TMessage );
procedure GridYCustomWndProc( var Msg: TMessage );
procedure TForm1.FormCreate(Sender: TObject);
begin
GridXWndProc := classes.MakeObjectInstance( GridXCustomWndProc );
GridXSaveWndProc := Pointer( GetWindowLong( GridX.Handle, GWL_WNDPROC ) );
SetWindowLong( GridX.Handle, GWL_WNDPROC, LongInt( GridXWndProc ) );
GridYWndProc := classes.MakeObjectInstance( GridYCustomWndProc );
GridYSaveWndProc := Pointer( GetWindowLong( GridY.Handle, GWL_WNDPROC ) );
SetWindowLong( GridY.Handle, GWL_WNDPROC, LongInt( GridYWndProc ) );
end;
procedure TForm1.GridXCustomWndProc( var Msg: TMessage );
begin
Msg.Result := CallWindowProc( GridXSaveWndProc, GridX.Handle, Msg.Msg, Msg.WParam, Msg.LParam );
case Msg.Msg of
WM_KEYDOWN:
begin
case TWMKey( Msg ).CharCode of VK_UP, VK_DOWN, VK_PRIOR, VK_NEXT:
GridY.Perform( Msg.Msg, Msg.WParam, Msg.LParam );
end;
end;
WM_VSCROLL:
GridY.Perform( Msg.Msg, Msg.WParam, Msg.LParam );
WM_HSCROLL:
GridY.Perform( Msg.Msg, Msg.WParam, Msg.LParam );
WM_MOUSEWHEEL:
begin
ActiveControl := GridY;
GridY.Perform( Msg.Msg, Msg.WParam, Msg.LParam );
end;
WM_DESTROY:
begin
SetWindowLong( GridX.Handle, GWL_WNDPROC, Longint( GridXSaveWndProc ) );
Classes.FreeObjectInstance( GridXWndProc );
end;
end;
end;
procedure TForm1.GridXMouseDown( Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer );
begin
GridY.SetActiveRow( GridX.GetActiveRow );
end;
procedure TForm1.GridYCustomWndProc( var Msg: TMessage );
begin
Msg.Result := CallWindowProc( GridYSaveWndProc, GridY.Handle, Msg.Msg, Msg.WParam, Msg.LParam );
case Msg.Msg of
WM_KEYDOWN:
begin
case TWMKey( Msg ).CharCode of VK_UP, VK_DOWN, VK_PRIOR, VK_NEXT:
GridX.Perform( Msg.Msg, Msg.WParam, Msg.LParam );
end;
end;
WM_VSCROLL:
GridX.Perform( Msg.Msg, Msg.WParam, Msg.LParam );
WM_HSCROLL:
GridX.Perform( Msg.Msg, Msg.WParam, Msg.LParam );
WM_MOUSEWHEEL:
begin
ActiveControl := GridX;
GridX.Perform( Msg.Msg, Msg.WParam, Msg.LParam );
end;
WM_DESTROY:
begin
SetWindowLong( GridY.Handle, GWL_WNDPROC, Longint( GridYSaveWndProc ) );
Classes.FreeObjectInstance( GridYWndProc );
end;
end;
end;
procedure TForm1.GridYMouseDown( Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer );
begin
GridX.SetActiveRow( GridY.GetActiveRow );
end;
感谢 - Sertac Akyuz 的解决方案。当使用网格集成到 VCL 表单应用程序中时,它们将在滚动和突出显示所选记录时相互模仿。