学习 Message(13): 解析 TWMMouse.Keys 参数

本例效果图:

---

代码文件:

---

unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs;



type

  TForm1 = class(TForm)

  protected

    procedure MyMouseDown(Msg: TWMMouse);

    procedure WMLButtonDown(var Message: TWMLButtonDown); message WM_LBUTTONDOWN;

    procedure WMMButtonDown(var Message: TWMMButtonDown); message WM_MBUTTONDOWN;

    procedure WMRButtonDown(var Message: TWMRButtonDown); message WM_RBUTTONDOWN;

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



procedure TForm1.MyMouseDown(Msg: TWMMouse);

var

  List: TStringList;

begin

  List := TStringList.Create;

  if Msg.Keys and MK_SHIFT   <> 0 then List.Add('Shift');

  if Msg.Keys and MK_CONTROL <> 0 then List.Add('Ctrl');

  if GetKeyState(VK_MENU)    < 0  then List.Add('Alt');

  if Msg.Keys and MK_LBUTTON <> 0 then List.Add('Left');

  if Msg.Keys and MK_MBUTTON <> 0 then List.Add('Middle');

  if Msg.Keys and MK_RBUTTON <> 0 then List.Add('Right');

  Canvas.TextOut(Msg.XPos, Msg.YPos, List.CommaText);

  List.Free;

end;



procedure TForm1.WMLButtonDown(var Message: TWMLButtonDown);

begin

  MyMouseDown(Message);

end;



procedure TForm1.WMMButtonDown(var Message: TWMMButtonDown);

begin

  MyMouseDown(Message);

end;



procedure TForm1.WMRButtonDown(var Message: TWMRButtonDown);

begin

  MyMouseDown(Message);

end;



end.


 
   

窗体文件:

---

object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 206

  ClientWidth = 339

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  PixelsPerInch = 96

  TextHeight = 13

end