Combobox中禁止鼠标中键滚动list列表

//第1种方法
procedure TForm1.FormMouseWheel(Sender: TObject; Shift: TShiftState;
WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
begin
if ActiveControl = ComboBox1 then
Handled := True;
end;
//第2种方法(了解该方法后，以后会有助于我们处理更复杂的问题)
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
cbb1: TComboBox;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
private
{ Private declarations }
FOldWndProc:  TWndMethod;
public
{ Public declarations }
procedure  NewWndProc(var  Message:  TMessage);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure  TForm1.NewWndProc(var  Message:  TMessage);
begin
if  ((Message.Msg  <>  WM_MOUSEWHEEL)  )  then
FOldWndProc(Message);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
FOldWndProc  :=  cbb1.WindowProc;
cbb1.WindowProc  :=  NewWndProc;

end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
cbb1.WindowProc  :=  FOldWndProc;
end;