学习 Message(2): 发送 WM_MOUSEMOVE 消息

本例效果图:

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代码文件:

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unit Unit1;



interface



uses

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

  Dialogs, StdCtrls, ExtCtrls;



type

  TForm1 = class(TForm)

    Panel1: TPanel;

    Button1: TButton;

    Button2: TButton;

    Button3: TButton;

    procedure Panel1MouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

    procedure Button3Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



{鼠标在 Panel1 中移动时, 我做了如下处理:}

{1、显示鼠标在 Panel1 中的坐标}

{2、显示是否同时按住了 Shift、Ctrl、Alt}

procedure TForm1.Panel1MouseMove(Sender: TObject; Shift: TShiftState; X,

  Y: Integer);

var

  List: TStringList;

begin

  List := TStringList.Create;

  if ssShift in Shift then List.Add('Shift');

  if ssCtrl  in Shift then List.Add('Ctrl');

  if ssAlt   in Shift then List.Add('Alt');



  if List.Count > 0 then

    Panel1.Caption := Format('%s: %d, %d', [List.CommaText, X, Y])

  else

    Panel1.Caption := Format('%d, %d', [X, Y]);



  List.Free;

end;



{向 Panel1 发送 WM_MOUSEMOVE 消息}

{第一个消息参数是 0, 表示没有按任何辅助键}

{第二个消息参数是 0, 相当于把鼠标移动到(0,0)坐标}

procedure TForm1.Button1Click(Sender: TObject);

begin

  Panel1.Perform(WM_MOUSEMOVE, 0, 0);

end;



{向 Panel1 发送 WM_MOUSEMOVE 消息}

{第二个消息参数在 WM_MOUSEMOVE 消息中表示鼠标坐标位置; 参数是32位整数, 低16位是X, 高16位是Y}

{这里给的坐标是控件的中心点}

procedure TForm1.Button2Click(Sender: TObject);

var

  x,y,LParam: Integer;

begin

  x := Panel1.ClientWidth div 2;

  y := Panel1.ClientHeight div 2;

  LParam := y shl 16 or x;

  Panel1.Perform(WM_MOUSEMOVE, 0, LParam);

end;



{向 Panel1 发送 WM_MOUSEMOVE 消息}

{消息的第一个参数是表示正在按下哪个辅助键和鼠标的状态}

{这里发送的消息是: 按着 Shift 键, 鼠标移动到 (20,10) 处}

procedure TForm1.Button3Click(Sender: TObject);

const

  x = 20;

  y = 10;

begin

  Panel1.Perform(WM_MOUSEMOVE, MK_SHIFT, y shl 16 or x);

end;



end.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 198

  ClientWidth = 255

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  PixelsPerInch = 96

  TextHeight = 13

  object Panel1: TPanel

    Left = 8

    Top = 8

    Width = 237

    Height = 121

    Caption = 'Panel1'

    TabOrder = 0

    OnMouseMove = Panel1MouseMove

  end

  object Button1: TButton

    Left = 8

    Top = 152

    Width = 75

    Height = 25

    Caption = 'Button1'

    TabOrder = 1

    OnClick = Button1Click

  end

  object Button2: TButton

    Left = 89

    Top = 152

    Width = 75

    Height = 25

    Caption = 'Button2'

    TabOrder = 2

    OnClick = Button2Click

  end

  object Button3: TButton

    Left = 170

    Top = 152

    Width = 75

    Height = 25

    Caption = 'Button3'

    TabOrder = 3

    OnClick = Button3Click

  end

end