Delphi编程实现清空回收站

本程序演示如何通过程序来清空回收站。

　　向窗体上添加一个TButton组件，它用于激活清空回收站的操作。设计完成的主界面如图1所示。

const

SHERB_NOCONFIRMATION = $00000001 ;

SHERB_NOPROGRESSUI = $00000002 ;

SHERB_NOSOUND = $00000004 ;

type

TSHEmptyRecycleBin=

function(Wnd:HWND;LPCTSTR:PChar;DWORD:Word):Integer;stdcall;
　　程序运行初期，程序首先会通过LoadLibrary函数加载动态链接库Shell32.dll，并且把加载后的操作句柄存储在LibHandle中。然后通过@SHEmptyRecycleBin:=GetProcAddress (LibHandle, ’SHEmptyRecycleBinA’)语句读取SHEmptyRecycleBinA函数的地址，如果以上语句能够正确执行(也就是@SHEmptyRecycleBin不等于nil)，那么就调用SHEmptyRecycleBin完成清空回收站的操作。最后释放动态链接库。响应代码如下：

procedure TForm1.Button1Click(Sender: TObject);
var
　SHEmptyRecycleBin:TSHEmptyRecycleBin;
　LibHandle:THandle;
begin
　LibHandle := LoadLibrary(PChar(’Shell32.dll’)) ;
　if LibHandle <> 0 then
　begin
　　@SHEmptyRecycleBin := GetProcAddress(LibHandle, ’SHEmptyRecycleBinA’);
　end
　else
　begin
　　MessageDlg(’Failed to load Shell32.dll.’, mtError, [mbOK], 0);
　　Exit ;
　end ;
　if @SHEmptyRecycleBin <> nil then
　begin
　　SHEmptyRecycleBin(Application.Handle,’’,SHERB_NOCONFIRMATION or
SHERB_NOPROGRESSUI or SHERB_NOSOUND) ;
　end;
　FreeLibrary(LibHandle);
　@SHEmptyRecycleBin := nil ;
end;
　　程序代码如下：

unit Unit1;

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

type
　TForm1 = class(TForm)
　Button1: TButton;
　procedure Button1Click(Sender: TObject);
private
　{ Private declarations }
public
　{ Public declarations }
end;

var
　Form1: TForm1;
　implementation
const
　SHERB_NOCONFIRMATION = $00000001 ;
　SHERB_NOPROGRESSUI = $00000002 ;
　SHERB_NOSOUND = $00000004 ;
type
　TSHEmptyRecycleBin=function(Wnd:HWND;LPCTSTR:PChar;DWORD:Word):Integer;stdcall;

　{$R *.dfm}
　procedure TForm1.Button1Click(Sender: TObject);
var
　SHEmptyRecycleBin:TSHEmptyRecycleBin;
　LibHandle:THandle;
begin
　LibHandle := LoadLibrary(PChar(’Shell32.dll’)) ;
　if LibHandle <> 0 then
　begin
　　@SHEmptyRecycleBin := GetProcAddress(LibHandle, ’SHEmptyRecycleBinA’);
　end
　else
　begin
　　MessageDlg(’Failed to load Shell32.dll.’, mtError, [mbOK], 0);
　　Exit ;
　end ;

　if @SHEmptyRecycleBin <> nil then
　begin
　　SHEmptyRecycleBin(Application.Handle,’’,SHERB_NOCONFIRMATION or SHERB_NOPROGRESSUI or SHERB_NOSOUND) ;
　end;
　FreeLibrary(LibHandle);
　@SHEmptyRecycleBin := nil ;
　end;
end.

　　保存文件，然后按F9键运行程序，程序运行的初始画面如图2所示。