/// <summary>
  /// 把数据文件导入到.xls文件
  /// </summary>
  /// <param name="ds"></param>
  public void ExportToExcel(DataSet ds)
  {

   if(ds.Tables.Count!=0)
   {
    //生成.xls文件完整路径名
    string tempFileName = GetTempFileName();
    object filename = EXCELPATH+tempFileName+EXCELPOSTFIX;
    object Nothing = System.Reflection.Missing.Value;
   
    //创建excel文件，文件名用系统时间生成精确到毫秒
    Excel.Application myExcel = new Excel.ApplicationClass();
    myExcel.Application.Workbooks.Add(Nothing);

    try
    {
     //把Dataset中的数据插入excel文件中
     int totalCount = 0;
     for(int k =0;k<ds.Tables.Count;k++)
     {
      int row = ds.Tables[k].Rows.Count;
      int column = ds.Tables[k].Columns.Count;
   
      for(int i = 0;i<column;i++)
      {
       myExcel.Cells[totalCount+2,1+i] = ds.Tables[k].Columns[i].ColumnName;
      }

      for(int i = 0;i<row;i++)
      {
       for(int j =0;j<column;j++)
       {
        myExcel.Cells[totalCount+3+i,1+j] = "'" + ds.Tables[k].Rows[i][j].ToString();
       }
      }
      totalCount = totalCount + row +4;
     }

     try
     {
      //保存excel文件到指定的目录下，文件名用系统时间生成精确到毫秒
      myExcel.ActiveWorkbook._SaveAs(filename,Nothing,Nothing,Nothing,Nothing,Nothing,XlSaveAsAccessMode.xlExclusive,Nothing,Nothing,Nothing,Nothing);
     }
     catch
     {
      System.Windows.Forms.MessageBox.Show("系统找不到指定目录下的文件：  "+EXCELPATH+tempFileName+EXCELPOSTFIX);
      return;
     }
     //让生成的excel文件可见
     myExcel.Visible = true;
    }
    catch(Exception e)
    {
     System.Windows.Forms.MessageBox.Show("向excel文件中写入数据出错：  " + e.Message);
    }
   }
   else
   {
    System.Windows.Forms.MessageBox.Show("No Data");
   }
  }