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用Delphi編程實現清空回收站功能

編輯：Delphi

本程序演示如何通過程序來清空回收站。

向窗體上添加一個TButton組件，它用於激活清空回收站的操作。

首先在程序的implementation段中定義3個常數和一個類型聲明，代碼如下：

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

程序運行初期，程序首先會通過LoadLibrary函數加載動態鏈接庫Shell32.dll，並且把加載後的操作句柄存儲在LibHandle中。然後通過@SHEmptyRecycleBin:=GetProcAddress (LibHandle, ’SHEmptyRecycleBinA’)語句讀取SHEmptyRecycleBinA函數的地址，如果以上語句能夠正確執行(也就是@SHEmptyRecycleBin不等於nil)，那麼就調用SHEmptyRecycleBin完成清空回收站的操作。最後釋放動態鏈接庫。響應代碼如下：

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;
            程序代碼如下：
            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.