Delphi实现窗口一直在桌面工作区内显示

分类：Delphi, System 阅读 (3,280) Add comments

11月 162013

转载请注明原文地址：http://bcoder.com/delphi/make-the-window-always-shows-in-desktop-workarea-in-delphi

　　有的时候我们要实现一个悬浮窗口，并使该窗口一直显示在桌面的工作区内。即整个窗口要一直显示在屏幕上，不能超出屏幕的上下左右边缘。此功能的实现也不难，我们需要自己写代码来响应窗口的WM_WINDOWPOSCHANGING消息，话不多说，详细代码如下供参考：

　　新建一个工程，并把下面代码拷贝到工程中，运行……

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
  private
    procedure WMWindowPosChanging(var Message: TWMWindowPosChanging); message WM_WINDOWPOSCHANGING;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.WMWindowPosChanging(var Message: TWMWindowPosChanging);
begin
  inherited;
  if (Message.WindowPos.y + Message.WindowPos.cy  > Screen.WorkAreaHeight) then begin
    Message.WindowPos.Y := Screen.WorkAreaHeight - Height ;
  end;
  if (Message.WindowPos.x + Message.WindowPos.cx > Screen.WorkAreaWidth) then begin
    Message.WindowPos.X := Screen.WorkAreaWidth - Width ;
  end;

  if Message.WindowPos.x < 0 then
    Message.WindowPos.x := 0;

  if Message.WindowPos.y < 0 then
    Message.WindowPos.y := 0;
end;

end.

unit Unit1;

interface

uses

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

Dialogs;

type

TForm1 = class(TForm)

private

procedure WMWindowPosChanging(var Message: TWMWindowPosChanging); message WM_WINDOWPOSCHANGING;

public

{ Public declarations }

end;

var

Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.WMWindowPosChanging(var Message: TWMWindowPosChanging);

begin

inherited;

if (Message.WindowPos.y + Message.WindowPos.cy > Screen.WorkAreaHeight) then begin

Message.WindowPos.Y := Screen.WorkAreaHeight - Height ;

end;

if (Message.WindowPos.x + Message.WindowPos.cx > Screen.WorkAreaWidth) then begin

Message.WindowPos.X := Screen.WorkAreaWidth - Width ;

end;

if Message.WindowPos.x < 0 then

Message.WindowPos.x := 0;

if Message.WindowPos.y < 0 then

Message.WindowPos.y := 0;

end;

end.

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