if IdFTP1.Connected then
try
  if TransferrignData then
    IdFTP1.Abort;
  IdFTP1.Quit;
finally
end
else
  with IdFTP1 do
  try
    Username := UserIDEdit.Text;
    Password := PasswordEdit.Text;
    Host := FtpServerEdit.Text;
    Connect;
    ChangeDir(CurrentDirEdit.Text);
  finally
  end;

LS := TStringList.Create;
try
  IdFTP1.ChangeDir(DirName);
  IdFTP1.TransferType := ftASCII;
  CurrentDirEdit.Text := IdFTP1.RetrieveCurrentDir;
  DirectoryListBox.Items.Clear;
  IdFTP1.List(LS);
  DirectoryListBox.Items.Assign(LS);
  if DirectoryListBox.Items.Count > 0 then
    if AnsiPos(total, DirectoryListBox.Items[0]) > 0 then
      DirectoryListBox.Items.Delete(0);
finally
  LS.Free;
end; 

IdFTP1.List(nil);   //获取当前目录的所有信息
//或者
IdFTP1.List(DirList);   //这个会得到列表的所有信息，包含时间、大小、类型等，相当于 IdFTP1.List(DirList,'',true);
//或者
IdFTP1.List(DirList,'',False);  //得到FTP路径下的所有文件夹名称 给到 DirList ，false只获取目录名称  ,这种方式获取的数据不包含数据类型的判断
//或者
IdFTP1.List;   //支持Delphi XE 版本
//或者
IdFTP1.List('',False);  //支持Delphi XE 版本


//看源代码：
procedure TIdFTP.List;
begin
  List(nil);
end;

procedure TIdFTP.List(const ASpecifier: string; ADetails: Boolean);
begin
  List(nil, ASpecifier, ADetails);
end;

procedure TIdFTP.List(ADest: TStrings; const ASpecifier: string = ''; ADetails: Boolean = True);      {do not localize}
var
  LDest: TMemoryStream;
  LTrans : TIdFTPTransferType;
begin
  if ADetails and UseMLIS and FCanUseMLS then begin
    ExtListDir(ADest, ASpecifier);
    Exit;
  end;
  // Note that for LIST, it might be best to put the connection in ASCII mode. because some old servers such as TOPS20 might require this.  We restore it if the original mode was not ASCII.  
　// It's a good idea to do this anyway because some clients still do this such as WS_FTP Pro and Microsoft's FTP Client.
  {注意，对于LIST，最好将连接设置为ASCII模式。因为像top20这样的旧服务器可能需要这个。如果原始模式不是ASCII，我们将恢复它。无论如何，这样做是一个好的方式，因为有些客户机仍然这样做，如WS_FTP Pro和微软的FTP客户机。}
  LTrans := TransferType;
  if LTrans <> ftASCII then begin
    Self.TransferType := ftASCII;
  end;
  try
    LDest := TMemoryStream.Create;
    try
      InternalGet(Trim(iif(ADetails, 'LIST', 'NLST') + ' ' + ASpecifier), LDest); {do not localize}
      FreeAndNil(FDirectoryListing);
      FDirFormat := '';
      LDest.Position := 0;
      FListResult.Text := ReadStringFromStream(LDest, -1, IOHandler.DefStringEncoding{$IFDEF STRING_IS_ANSI}, IOHandler.DefAnsiEncoding{$ENDIF});
      TIdFTPListResult(FListResult).FDetails := ADetails;
      TIdFTPListResult(FListResult).FUsedMLS := False;
      // FDirFormat will be updated in ParseFTPList...
    finally
      FreeAndNil(LDest);
    end;
    if ADest <> nil then begin
      ADest.Assign(FListResult);
    end;
    DoOnRetrievedDir;
  finally
    if LTrans <> ftASCII then begin
      TransferType := LTrans;
    end;
  end;
end;

SaveDialog1.FileName := Name;
if SaveDialog1.Execute then
begin
  SetFunctionButtons(false);
  IdFTP1.TransferType := ftBinary;
  BytesToTransfer := IdFTP1.Size(Name);
  if FileExists(Name) then
  begin
    case MessageDlg('File aready exists. Do you want to resume the download operation?', mtConfirmation, mbYesNoCancel, 0) of
      mrYes:
        begin
          BytesToTransfer := BytesToTransfer - FileSizeByName(Name);
          IdFTP1.Get(Name, SaveDialog1.FileName, false, true);
        end;
      mrNo:
        begin
          IdFTP1.Get(Name, SaveDialog1.FileName, true);
        end;
      mrCancel:
        begin
          exit;
        end;
    end;
  end
  else
  begin
    IdFTP1.Get(Name, SaveDialog1.FileName, false);
  end;
end;

if IdFTP1.Connected then
begin
  if UploadOpenDialog1.Execute then
  try
    IdFTP1.TransferType := ftBinary;
    IdFTP1.Put(UploadOpenDialog1.FileName, ExtractFileName(UploadOpenDialog1.FileName));//可以在此添加改变目录的代码;
  finally
    //完成清除工作
  end;
end;

if not IdFTP1.Connected then
  exit;
Name := IdFTP1.DirectoryListing.Items[iCurrSelect].FileName;
if IdFTP1.DirectoryListing.Items[iCurrSelect].ItemType = ditDirectory then
try
  idftp1.RemoveDir(Name);
finally
end
else
try
  idftp1.Delete(Name);
finally
end;