unit ScrollHelper;
 
interface
 
Uses
  Classes,
  Windows,
  DBGrids,
  Messages,
  Controls;
 
Type
  TScrollHelper = Class(TObject)
  Private
  Protected
    FGrid : TDBGrid;
    FOldProc : TWndMethod;
    Procedure GridProc(Var Msg : TMessage);
  Public
    Constructor Create(Grid : TDBGrid);
    Destructor Destroy(); Override;
  Published
  End; {TScrollHelper}
 
implementation
 
Const
  WM_MOUSEWHEELUP = 120;
  WM_MOUSEWHEELDOWN = 65416;
 
{ TScrollHelper }
 
constructor TScrollHelper.Create(Grid : TDBGrid);
begin
  Inherited Create();
  FGrid := Grid;
  FOldProc := FGrid.WindowProc;
  FGrid.WindowProc := GridProc;
end;
 
destructor TScrollHelper.Destroy;
begin
  FGrid.WindowProc := FOldProc;
  Inherited;
end;
 
procedure TScrollHelper.GridProc(var Msg: TMessage);
begin
  If (Msg.Msg = WM_MOUSEWHEEL) Then
  Begin
    Case Msg.WParamHi Of
      WM_MOUSEWHEELUP: FGrid.DataSource.DataSet.Prior();
      WM_MOUSEWHEELDOWN: FGrid.DataSource.DataSet.Next();
    End; {Case}
  End Else Begin
    FOldProc(Msg);
  End;
end;
 
end.