使用线程复制主线程添加到字符串列表的文件

我有一个网页创建程序,当建立一个网站,创建数百个文件。

当Internet根文件夹位于本地PC上时,程序运行正常。如果Internet根文件夹位于网络驱动器上,则复制创建的页面比创建页面本身花费的时间更长(页面的创建相当优化)。

我正在考虑在本地创建文件,将创建的文件的名称添加到tstringlist,并让另一个线程将其复制到网络驱动器(从tstringlist中删除复制的文件)。

但是,我以前从未使用过线程,在其他涉及线程的Delphi问题中我找不到现有的答案。( 如果我们能用 and 搜索字段中的运算符 ,所以我现在要问是否有人有一个工作的例子,它是这样做的(或者可以向我指出一些使用Delphi代码的文章)?

我用的是Delphi7。

编辑:我的示例项目(THX到原始代码 mghie -在此再次感谢)。

  ...
  fct : TFileCopyThread;
  ...

  procedure TfrmMain.FormCreate(Sender: TObject);
  begin
     if not DirectoryExists(DEST_FOLDER)
     then
        MkDir(DEST_FOLDER);
     fct := TFileCopyThread.Create(Handle, DEST_FOLDER);
  end;


  procedure TfrmMain.FormClose(Sender: TObject; var Action: TCloseAction);
  begin
     FreeAndNil(fct);
  end;

  procedure TfrmMain.btnOpenClick(Sender: TObject);
  var sDir : string;
      Fldr : TedlFolderRtns;
      i : integer;
  begin
     if PickFolder(sDir,'')
     then begin
        // one of my components, returning a filelist [non threaded  :) ] 
        Fldr := TedlFolderRtns.Create();
        Fldr.FileList(sDir,'*.*',True);
        for i := 0 to Fldr.TotalFileCnt -1 do
        begin
           fct.AddFile( fldr.ResultList[i]);
        end;
     end;
  end;

  procedure TfrmMain.wmFileBeingCopied(var Msg: Tmessage);
  var s : string;
  begin
     s := fct.FileBeingCopied;
     if s <> ''
     then
        lbxFiles.Items.Add(fct.FileBeingCopied);
     lblFileCount.Caption := IntToStr( fct.FileCount );
  end;

单位

  unit eFileCopyThread;
  interface
  uses
     SysUtils, Classes, SyncObjs, Windows, Messages;
  const
    umFileBeingCopied = WM_USER + 1;
  type

    TFileCopyThread = class(TThread)
    private
      fCS: TCriticalSection;
      fDestDir: string;
      fSrcFiles: TStrings;
      fFilesEvent: TEvent;
      fShutdownEvent: TEvent;
      fFileBeingCopied: string;
      fMainWindowHandle: HWND;
      fFileCount: Integer;
      function GetFileBeingCopied: string;
    protected
      procedure Execute; override;
    public
      constructor Create(const MainWindowHandle:HWND; const ADestDir: string);
      destructor Destroy; override;

      procedure AddFile(const ASrcFileName: string);
      function IsCopyingFiles: boolean;
      property FileBeingCopied: string read GetFileBeingCopied;
      property FileCount: Integer read fFileCount;
    end;

  implementation
  constructor TFileCopyThread.Create(const MainWindowHandle:HWND;const ADestDir: string);
  begin
    inherited Create(True);
    fMainWindowHandle := MainWindowHandle;
    fCS := TCriticalSection.Create;
    fDestDir := IncludeTrailingBackslash(ADestDir);
    fSrcFiles := TStringList.Create; 
    fFilesEvent := TEvent.Create(nil, True, False, ''); 
    fShutdownEvent := TEvent.Create(nil, True, False, ''); 
    Resume; 
  end; 

  destructor TFileCopyThread.Destroy; 
  begin 
    if fShutdownEvent <> nil then 
      fShutdownEvent.SetEvent; 
    Terminate;
    WaitFor;
    FreeAndNil(fFilesEvent);
    FreeAndNil(fShutdownEvent);
    FreeAndNil(fSrcFiles);
    FreeAndNil(fCS);
    inherited;
  end;

  procedure TFileCopyThread.AddFile(const ASrcFileName: string);
  begin
    if ASrcFileName <> ''
    then begin
      fCS.Acquire;
      try
        fSrcFiles.Add(ASrcFileName);
        fFileCount := fSrcFiles.Count;
        fFilesEvent.SetEvent;
      finally
        fCS.Release;
      end;
    end;
  end;

  procedure TFileCopyThread.Execute;
  var
    Handles: array[0..1] of THandle;
    Res: Cardinal;
    SrcFileName, DestFileName: string;
  begin
    Handles[0] := fFilesEvent.Handle;
    Handles[1] := fShutdownEvent.Handle;
    while not Terminated do
    begin
      Res := WaitForMultipleObjects(2, @Handles[0], False, INFINITE);
      if Res = WAIT_OBJECT_0 + 1 then
        break;
      if Res = WAIT_OBJECT_0
      then begin
        while not Terminated do
        begin
          fCS.Acquire;
          try
            if fSrcFiles.Count > 0
            then begin
              SrcFileName := fSrcFiles[0];
              fSrcFiles.Delete(0);
              fFileCount := fSrcFiles.Count;
              PostMessage( fMainWindowHandle,umFileBeingCopied,0,0 );
           end else
               SrcFileName := '';
           fFileBeingCopied := SrcFileName;
            if SrcFileName = '' then
              fFilesEvent.ResetEvent;
          finally
            fCS.Release;
          end;

          if SrcFileName = '' then
            break;
          DestFileName := fDestDir + ExtractFileName(SrcFileName);
          CopyFile(PChar(SrcFileName), PChar(DestFileName), True);
        end;
      end;
    end;
  end;

  function TFileCopyThread.IsCopyingFiles: boolean;
  begin 
    fCS.Acquire; 
    try 
      Result := (fSrcFiles.Count > 0) 
        // last file is still being copied 
        or (WaitForSingleObject(fFilesEvent.Handle, 0) = WAIT_OBJECT_0); 
    finally 
      fCS.Release; 
    end; 
  end; 

  // new version - edited after receiving comments 
  function TFileCopyThread.GetFileBeingCopied: string; 
  begin 
     fCS.Acquire; 
     try 
        Result := fFileBeingCopied; 
     finally 
        fCS.Release; 
     end; 
  end; 

  // old version - deleted after receiving comments 
  //function TFileCopyThread.GetFileBeingCopied: string;
  //begin
  //  Result := '';
  //  if fFileBeingCopied <> ''
  //  then begin
  //    fCS.Acquire;
  //    try
  //      Result := fFileBeingCopied;
  //      fFilesEvent.SetEvent;
  //    finally
  //      fCS.Release;
  //    end;
  //  end;
  //end;

  end.

如有其他意见,我们将不胜感激。

阅读评论并查看示例,您会发现解决方案的不同方法,对所有这些方法都有赞成和反对的评论。

当试图实现一个复杂的新特性(线程对我来说)时,问题是,您几乎总是会发现一些似乎有效的东西…起先。直到后来你才发现事情本来应该以不同的方式进行的。线程就是一个很好的例子。

像StackOverflow这样的网站很不错。多好的社区啊。