C# 文件上传下载(Excel导入,多线程下载)功能的实现代码

//打开excel文件，转换为datatable
　　　　　 datatable dtexcel;
　　　　private void openfile()
　　　 {
　　　　　　openfiledialog dialog = new openfiledialog();
　　　　　　dialog.filter = "microsoft excel files(*.xls)|*.xls;*.xlsx"; //筛选打开文件类型 ：图片 *.jpg|*.jpg|*.bmp|*.bmp ;"音频文|*.mp3;*.wma;*.aac;*.midi;*.wav" 等等
　　　　　　if (dialog.showdialog() == dialogresult.ok)
　　　　　　{
　　　　　　　　dialogfilename = dialog.filename;
　　　　　　　　dtexcel = exceltodatatable(dialogfilename, "sheet1", true);
　　　　　　}
　　　　}
/// <summary>
  /// excel转datatable
  /// </summary>
  /// <param name="filename">文件名含后缀名</param>
  /// <param name="sheetname">excel文件，页名称</param>
  /// <param name="isfirstrowcolumn">是否将第一列作为表头</param>
  /// <returns></returns>
  private datatable exceltodatatable(string filename, string sheetname, bool isfirstrowcolumn)
  {
   iworkbook workbook = null;
   filestream fs = null;
   isheet sheet = null;
   datatable data = new datatable();
   int startrow = 0;
   try
   {
    fs = new filestream(filename, filemode.open, fileaccess.read);
    if (filename.indexof(".xlsx") > 0) // 2007版本
     workbook = new xssfworkbook(fs);
    else if (filename.indexof(".xls") > 0) // 2003版本
     workbook = new hssfworkbook(fs);
    if (sheetname != null)
    {
     sheet = workbook.getsheet(sheetname);
     if (sheet == null) //如果没有找到指定的sheetname对应的sheet，则尝试获取第一个sheet
     {
      sheet = workbook.getsheetat(0);
     }
    }
    else
    {
     sheet = workbook.getsheetat(0);
    }
    if (sheet != null)
    {
     irow firstrow = sheet.getrow(0);
     int cellcount = firstrow.lastcellnum; //一行最后一个cell的编号 即总的列数
     if (isfirstrowcolumn)
     {
      for (int i = firstrow.firstcellnum; i < cellcount; ++i)
      {
       icell cell = firstrow.getcell(i);
       if (cell != null)
       {
        string cellvalue = cell.stringcellvalue;
        if (cellvalue != null)
        {
         datacolumn column = new datacolumn(cellvalue);
         data.columns.add(column);
        }
       }
      }
      startrow = sheet.firstrownum + 1;
     }
     else
     {
      startrow = sheet.firstrownum;
     }
     //最后一列的标号
     int rowcount = sheet.lastrownum;
     for (int i = startrow; i <= rowcount; ++i)
     {
      irow row = sheet.getrow(i);
      if (row == null) continue; //没有数据的行默认是null　　　　　　　
      datarow datarow = data.newrow();
      for (int j = row.firstcellnum; j < cellcount; ++j)
      {
       if (row.getcell(j) != null) //同理，没有数据的单元格都默认是null
        datarow[j] = row.getcell(j).tostring();
      }
      data.rows.add(datarow);
     }
    }
    return data;
   }
   catch (exception ex)
   {
    mymessagebox.show(ex.message);
    return null;
   }
  }

private void download()
  {
   if (impdefinebm != null)
   {
    folderbrowserdialog path = new folderbrowserdialog();
    path.showdialog();
    if (path != null && path.selectedpath != "")
    {
     string url = @"http://192.168.1.1/xx.xls";  //下载地址
     string name = "filename";　　　　　　　　　　　　　　//　文件名称
     string savefilepath = path.selectedpath + "\\" + name + url.substring(url.lastindexof(".")); //注意：下载文件名的命名 ，可根据实际需求调整调用的文件创建方式
     multidownload download = new multidownload(5, url, savefilepath); //调用多线程下载
     download.start();
    }
   }
  }
 #region 多线程下载
  public class multidownload
  {
   #region 变量
   private int _threadnum;    //线程数量
   private long _filesize;    //文件大小
   private string _fileurl;   //文件地址
   private string _filename;   //文件名
   private string _savepath;   //保存路径
   private short _threadcompletenum; //线程完成数量
   private bool _iscomplete;   //是否完成
   private volatile int _downloadsize; //当前下载大小(实时的)
   private thread[] _thread;   //线程数组
   private list<string> _tempfiles = new list<string>();
   private object locker = new object();
   #endregion
   #region 属性
   /// <summary>
   /// 文件名
   /// </summary>
   public string filename
   {
    get
    {
     return _filename;
    }
    set
    {
     _filename = value;
    }
   }
   /// <summary>
   /// 文件大小
   /// </summary>
   public long filesize
   {
    get
    {
     return _filesize;
    }
   }
   /// <summary>
   /// 当前下载大小(实时的)
   /// </summary>
   public int downloadsize
   {
    get
    {
     return _downloadsize;
    }
   }
   /// <summary>
   /// 是否完成
   /// </summary>
   public bool iscomplete
   {
    get
    {
     return _iscomplete;
    }
   }
   /// <summary>
   /// 线程数量
   /// </summary>
   public int threadnum
   {
    get
    {
     return _threadnum;
    }
   }
   /// <summary>
   /// 保存路径
   /// </summary>
   public string savepath
   {
    get
    {
     return _savepath;
    }
    set
    {
     _savepath = value;
    }
   }
   #endregion
   /// <summary>
   /// 构造函数
   /// </summary>
   /// <param name="threahnum">线程数量</param>
   /// <param name="fileurl">文件url路径</param>
   /// <param name="savepath">本地保存路径</param>
   public multidownload(int threahnum, string fileurl, string savepath)
   {
    this._threadnum = threahnum;
    this._thread = new thread[threahnum];
    this._fileurl = fileurl;
    this._savepath = savepath;
   }
   public void start()
   {
    httpwebrequest request = (httpwebrequest)webrequest.create(_fileurl);
    httpwebresponse response = (httpwebresponse)request.getresponse();
    _filesize = response.contentlength;
    int singelnum = (int)(_filesize / _threadnum);  //平均分配
    int remainder = (int)(_filesize % _threadnum);  //获取剩余的
    request.abort();
    response.close();
    for (int i = 0; i < _threadnum; i++)
    {
     list<int> range = new list<int>();
     range.add(i * singelnum);
     if (remainder != 0 && (_threadnum - 1) == i) //剩余的交给最后一个线程
      range.add(i * singelnum + singelnum + remainder - 1);
     else
      range.add(i * singelnum + singelnum - 1);
     //下载指定位置的数据
     int[] ran = new int[] { range[0], range[1] };
     _thread[i] = new thread(new parameterizedthreadstart(download));
     _thread[i].name = system.io.path.getfilenamewithoutextension(_fileurl) + "_{0}".replace("{0}", convert.tostring(i + 1));
     _thread[i].start(ran);
    }
    //messagebox.show("下载完成！");
   }
   private void download(object obj)
   {
    stream httpfilestream = null, localfilestram = null;
    try
    {
     int[] ran = obj as int[];
     string tmpfileblock = system.io.path.gettemppath() + thread.currentthread.name + ".tmp";
     _tempfiles.add(tmpfileblock);
     httpwebrequest httprequest = (httpwebrequest)webrequest.create(_fileurl);
     httprequest.addrange(ran[0], ran[1]);
     httpwebresponse httpresponse = (httpwebresponse)httprequest.getresponse();
     httpfilestream = httpresponse.getresponsestream();
     localfilestram = new filestream(tmpfileblock, filemode.create);
     byte[] by = new byte[5000];
     int getbytesize = httpfilestream.read(by, 0, (int)by.length); //read方法将返回读入by变量中的总字节数
     while (getbytesize > 0)
     {
      thread.sleep(20);
      lock (locker) _downloadsize += getbytesize;
      localfilestram.write(by, 0, getbytesize);
      getbytesize = httpfilestream.read(by, 0, (int)by.length);
     }
     lock (locker) _threadcompletenum++;
    }
    catch (exception ex)
    {
     throw new exception(ex.message.tostring());
    }
    finally
    {
     if (httpfilestream != null) httpfilestream.dispose();
     if (localfilestram != null) localfilestram.dispose();
    }
    if (_threadcompletenum == _threadnum)
    {
     complete();
     _iscomplete = true;
    }
   }
   /// <summary>
   /// 下载完成后合并文件块
   /// </summary>
   private void complete()
   {
    stream mergefile = null;
    binarywriter addwriter = null;
    try
    {
     using (mergefile = new filestream(@_savepath, filemode.create)) //根据实际情况调整filemode
     {
      addwriter = new binarywriter(mergefile);
      foreach (string file in _tempfiles)
      {
       using (filestream fs = new filestream(file, filemode.open))
       {
        binaryreader tempreader = new binaryreader(fs);
        addwriter.write(tempreader.readbytes((int)fs.length));
        tempreader.close();
       }
       file.delete(file);
      }
     }
     mymessagebox.show("下载完成！");
    }
    catch (exception ex)
    {
     throw new exception(ex.message);
    }
    finally
    {
     if (addwriter != null)
     {
      addwriter.close();
      addwriter.dispose();
     }
     if (mergefile != null)
     {
      mergefile.close();
      mergefile.dispose();
     }
    }
   }
  }