滚动鼠标滚轮德尔福

Question

如何将OnMouseWheel添加到两个滚动框的相同表单中？我将方法应用于ScrollBox1，但我不知道如何将方法添加到ScrollBox2

procedure TForm3.FormMouseWheel(Sender: TObject; Shift: TShiftState;
  WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
var
  LTopLeft, LTopRight, LBottomLeft, LBottomRight: SmallInt;
  LPoint: TPoint;
begin
   inherited;
  LPoint := ScrollBox1.ClientToScreen(Point(0,0));

  LTopLeft := LPoint.X;
  LTopRight := LTopLeft + ScrollBox1.Width;

  LBottomLeft := LPoint.Y;
  LBottomRight := LBottomLeft + ScrollBox1.Width;


  if (MousePos.X >= LTopLeft) and
    (MousePos.X <= LTopRight) and
    (MousePos.Y >= LBottomLeft)and
    (MousePos.Y <= LBottomRight) then
  begin
    ScrollBox1.VertScrollBar.Position :=
    ScrollBox1.VertScrollBar.Position - WheelDelta;

    Handled := True;
  end;
end;

Answer 1

将相同的处理程序分配给两个ScrollBox组件，而不是Form，然后使用Sender参数来知道哪个组件正在调用处理程序。

procedure TForm3.ScrollBoxMouseWheel(Sender: TObject;
  Shift: TShiftState; WheelDelta: Integer; MousePos: TPoint;
  var Handled: Boolean);
var
  LTopLeft, LTopRight, LBottomLeft, LBottomRight: SmallInt;
  LPoint: TPoint;
  ScrollBox: TScrollBox;
begin
  ScrollBox := TScrollBox(Sender);
  LPoint := ScrollBox.ClientToScreen(Point(0,0));
  LTopLeft := LPoint.X;
  LTopRight := LTopLeft + ScrollBox.ClientWidth;
  LBottomLeft := LPoint.Y;
  LBottomRight := LBottomLeft + ScrollBox.ClientWidth;
  if (MousePos.X >= LTopLeft) and
    (MousePos.X <= LTopRight) and
    (MousePos.Y >= LBottomLeft) and
    (MousePos.Y <= LBottomRight) then
  begin
    ScrollBox.VertScrollBar.Position := ScrollBox.VertScrollBar.Position - WheelDelta;
    Handled := True;
  end;
end;

Answer 2

Uses Math;

procedure TMainForm.ScrollBoxMouseWheel(Sender: TObject; Shift: TShiftState;
  WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
var
  ScrollBox: TScrollBox;
  NewPos: Integer;
begin
  ScrollBox := TScrollBox(Sender);

  NewPos:= ScrollBox.VertScrollBar.Position - WheelDelta div 10;  // sensitivity
  NewPos:= Max(NewPos, 0);
  NewPos:= Min(NewPos, ScrollBox.VertScrollBar.Range);

  ScrollBox.VertScrollBar.Position := NewPos;
  Handled := True;
end;