unit1.~pas

《Delphi 7应用编程150例》源码（全）

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
    procedure ClipboardChanged(var AMessage: TMessage); message WM_DRAWCLIPBOARD;
    //处理WM_DRAWCLIPBOARD消息过程
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  NextClipHwnd:HWND;
  //观察链中下一个窗口句柄

implementation

{$R *.dfm}
procedure TForm1.ClipboardChanged(var AMessage: TMessage);
begin
  SendMessage(NextClipHwnd,AMessage.Msg,AMessage.WParam,AMessage.LParam);
  //将WM_DRAWCLIPBOARD消息传递到下一个观察链中的窗口
  if (Clipboard.HasFormat(CF_TEXT) or Clipboard.HasFormat(CF_OEMTEXT)) then
  begin
    Memo1.Lines.Text:=Clipboard.asText;
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  NextClipHwnd:=SetClipBoardViewer(Handle);
  //获得观察链中下一个窗口句柄
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  ChangeClipboardChain(Handle,NextClipHwnd);
  //从观察链中删除本观察窗口
  SendMessage(NextClipHwnd,WM_CHANGECBCHAIN,Handle,NextClipHwnd);
  //将WM_DRAWCLIPBOARD消息传递到下一个观察链中的窗口
end;

end.