DataTable中的数据导出Excel文件

/// <summary>
   /// 将DataTable中的数据导出到指定的Excel文件中
   /// </summary>
   /// <param name="page">Web页面对象</param>
   /// <param name="tab">包含被导出数据的DataTable对象</param>
   /// <param name="FileName">Excel文件的名称</param>
   public static void Export(System.Web.UI.Page page,System.Data.DataTable tab,string FileName)
   {
    System.Web.HttpResponse httpResponse = page.Response;
    System.Web.UI.WebControls.DataGrid dataGrid=new System.Web.UI.WebControls.DataGrid();
    dataGrid.DataSource=tab.DefaultView;
    dataGrid.AllowPaging = false;
    dataGrid.HeaderStyle.BackColor = System.Drawing.Color.Green;
    dataGrid.HeaderStyle.HorizontalAlign = HorizontalAlign.Center;
    dataGrid.HeaderStyle.Font.Bold = true;
    dataGrid.DataBind();
    httpResponse.AppendHeader("Content-Disposition","attachment;filename="+HttpUtility.UrlEncode(FileName,System.Text.Encoding.UTF8)); //filename="*.xls";
    httpResponse.ContentEncoding=System.Text.Encoding.GetEncoding("GB2312");
    httpResponse.ContentType ="application/ms-excel";
    System.IO.StringWriter tw = new System.IO.StringWriter() ;
    System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter (tw);
    dataGrid.RenderControl(hw);
   
    string filePath = page.Server.MapPath("..")+"\\Files\\" +FileName;
    System.IO.StreamWriter sw = System.IO.File.CreateText(filePath);
    sw.Write(tw.ToString());
    sw.Close();

    DownFile(httpResponse,FileName,filePath);
  
    httpResponse.End();
   }
private static bool DownFile(System.Web.HttpResponse Response,string fileName,string fullPath)
   {
    try
    {
     Response.ContentType = "application/octet-stream";
    
     Response.AppendHeader("Content-Disposition","attachment;filename=" +
      HttpUtility.UrlEncode(fileName,System.Text.Encoding.UTF8) + ";charset=GB2312");
     System.IO.FileStream fs= System.IO.File.OpenRead(fullPath);
     long fLen=fs.Length;
     int size=102400;//每100K同时下载数据
     byte[] readData = new byte[size];//指定缓冲区的大小
     if(size>fLen)size=Convert.ToInt32(fLen);
     long fPos=0;
     bool isEnd=false;
     while (!isEnd)
     {
      if((fPos+size)>fLen)
      {
       size=Convert.ToInt32(fLen-fPos);
       readData = new byte[size];
       isEnd=true;
      }
      fs.Read(readData, 0, size);//读入一个压缩块
      Response.BinaryWrite(readData);
      fPos+=size;
     }
     fs.Close();
     System.IO.File.Delete(fullPath);
     return true;
    }
    catch
    {
     return false;
    }
   }

将指定Excel文件中的数据转换成DataTable
/// <summary>
   /// 将指定Excel文件中的数据转换成DataTable对象，供应用程序进一步处理
   /// </summary>
   /// <param name="filePath"></param>
   /// <returns></returns>
   public static System.Data.DataTable Import(string filePath)
   {
    System.Data.DataTable rs = new System.Data.DataTable();
    bool canOpen=false;
   
    OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;"+
     "Data Source=" + filePath + ";" +
     "Extended Properties=\"Excel 8.0;\"");
    
    try//尝试数据连接是否可用
    {
     conn.Open();
     conn.Close();
     canOpen=true;
    }
    catch{}

    if(canOpen)
    {
     try//如果数据连接可以打开则尝试读入数据
     {
      OleDbCommand myOleDbCommand = new OleDbCommand("SELECT * FROM [Sheet1$]",conn);
      OleDbDataAdapter myData = new OleDbDataAdapter(myOleDbCommand);
      myData.Fill(rs);
      conn.Close();
     }
     catch//如果数据连接可以打开但是读入数据失败，则从文件中提取出工作表的名称，再读入数据
     {
      string sheetName=GetSheetName(filePath);
      if(sheetName.Length>0)
      {
       OleDbCommand myOleDbCommand = new OleDbCommand("SELECT * FROM ["+sheetName+"$]",conn);
       OleDbDataAdapter myData = new OleDbDataAdapter(myOleDbCommand);
       myData.Fill(rs);
       conn.Close();
      }
     }
    }
    else
    {
     System.IO.StreamReader tmpStream=File.OpenText(filePath);
     string tmpStr=tmpStream.ReadToEnd();
     tmpStream.Close();
     rs=GetDataTableFromString(tmpStr);
     tmpStr="";
    }
    return rs;
   }
/// <summary>
   /// 将指定Html字符串的数据转换成DataTable对象 --根据“<tr><td>”等特殊字符进行处理
   /// </summary>
   /// <param name="tmpHtml">Html字符串</param>
   /// <returns></returns>
   private static DataTable GetDataTableFromString(string tmpHtml)
   {
    string tmpStr=tmpHtml;
    DataTable TB=new DataTable();
    //先处理一下这个字符串，删除第一个<tr>之前合最后一个</tr>之后的部分
    int index=tmpStr.IndexOf("<tr");
    if(index>-1)
     tmpStr=tmpStr.Substring(index);
    else
     return TB;

    index=tmpStr.LastIndexOf("</tr>");
    if(index>-1)
     tmpStr=tmpStr.Substring(0,index+5);
    else
     return TB;

    bool existsSparator=false;
    char Separator=Convert.ToChar("^");

    //如果原字符串中包含分隔符“^”则先把它替换掉
    if(tmpStr.IndexOf(Separator.ToString())>-1)
    {
     existsSparator=true;
     tmpStr=tmpStr.Replace("^","^$&^");
    }

    //先根据“</tr>”分拆
    string[] tmpRow=tmpStr.Replace("</tr>","^").Split(Separator);

    for(int i=0;i<tmpRow.Length-1;i++)
    {
     DataRow newRow=TB.NewRow();

     string tmpStrI=tmpRow[i];
     if(tmpStrI.IndexOf("<tr")>-1)
     {
      tmpStrI=tmpStrI.Substring(tmpStrI.IndexOf("<tr"));
      if(tmpStrI.IndexOf("display:none")<0||tmpStrI.IndexOf("display:none")>tmpStrI.IndexOf(">"))
      {
       tmpStrI=tmpStrI.Replace("</td>","^");
       string[] tmpField=tmpStrI.Split(Separator);
    
       for(int j=0;j<tmpField.Length-1;j++)
       {
        tmpField[j]=RemoveString(tmpField[j],"<font>");
        index=tmpField[j].LastIndexOf(">")+1;
        if(index>0)
        {
         string field=tmpField[j].Substring(index,tmpField[j].Length-index);
         if(existsSparator) field=field.Replace("^$&^","^");
         if(i==0)
         {
          string tmpFieldName=field;
          int sn=1;
          while(TB.Columns.Contains(tmpFieldName))
          {
           tmpFieldName=field+sn.ToString();
           sn+=1;
          }
          TB.Columns.Add(tmpFieldName);
         }
         else
         {
          newRow[j]=field;
         }
        }//end of if(index>0)
       }

       if(i>0)
        TB.Rows.Add(newRow);
      }
     }
    }

    TB.AcceptChanges();
    return TB;
   }

   /// <summary>
   /// 从指定Html字符串中剔除指定的对象
   /// </summary>
   /// <param name="tmpHtml">Html字符串</param>
   /// <param name="remove">需要剔除的对象--例如输入"<font>"则剔除"<font ???????>"和"</font>>"</param>
   /// <returns></returns>
   public static string RemoveString(string tmpHtml,string remove)
   {
    tmpHtml=tmpHtml.Replace(remove.Replace("<","</"),"");
    tmpHtml=RemoveStringHead(tmpHtml,remove);
    return tmpHtml;
   }
   /// <summary>
   /// 只供方法RemoveString()使用
   /// </summary>
   /// <returns></returns>
   private static string RemoveStringHead(string tmpHtml,string remove)
   {
    //为了方便注释，假设输入参数remove="<font>"
    if(remove.Length<1) return tmpHtml;//参数remove为空：不处理返回
    if((remove.Substring(0,1)!="<")||(remove.Substring(remove.Length-1)!=">")) return tmpHtml;//参数remove不是<?????>：不处理返回

    int IndexS=tmpHtml.IndexOf(remove.Replace(">",""));//查找“<font”的位置
    int IndexE=-1;
    if(IndexS>-1)
    {
     string tmpRight=tmpHtml.Substring(IndexS,tmpHtml.Length-IndexS);
     IndexE=tmpRight.IndexOf(">");
     if(IndexE>-1)
      tmpHtml=tmpHtml.Substring(0,IndexS)+tmpHtml.Substring(IndexS+IndexE+1);
     if(tmpHtml.IndexOf(remove.Replace(">",""))>-1)
      tmpHtml=RemoveStringHead(tmpHtml,remove);
    }
    return tmpHtml;
   }

   /// <summary>
   /// 将指定Excel文件中读取第一张工作表的名称
   /// </summary>
   /// <param name="filePath"></param>
   /// <returns></returns>
   private static string GetSheetName(string filePath)
   {
    string sheetName="";

    System.IO.FileStream tmpStream=File.OpenRead(filePath);
    byte[] fileByte=new byte[tmpStream.Length];
    tmpStream.Read(fileByte,0,fileByte.Length);
    tmpStream.Close();
   
    byte[] tmpByte=new byte[]{Convert.ToByte(11),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),
           Convert.ToByte(11),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),
           Convert.ToByte(30),Convert.ToByte(16),Convert.ToByte(0),Convert.ToByte(0)};
   
    int index=GetSheetIndex(fileByte,tmpByte);
    if(index>-1)
    {

     index+=16+12;
     System.Collections.ArrayList sheetNameList=new System.Collections.ArrayList();
    
     for(int i=index;i<fileByte.Length-1;i++)
     {
      byte temp=fileByte[i];
      if(temp!=Convert.ToByte(0))
       sheetNameList.Add(temp);
      else
       break;
     }
     byte[] sheetNameByte=new byte[sheetNameList.Count];
     for(int i=0;i<sheetNameList.Count;i++)
      sheetNameByte[i]=Convert.ToByte(sheetNameList[i]);
   
     sheetName=System.Text.Encoding.Default.GetString(sheetNameByte);
    }
    return sheetName;
   }
   /// <summary>
   /// 只供方法GetSheetName()使用
   /// </summary>
   /// <returns></returns>
   private static int GetSheetIndex(byte[] FindTarget,byte[] FindItem)
   {
    int index=-1;

    int FindItemLength=FindItem.Length;
    if(FindItemLength<1) return -1;
    int FindTargetLength=FindTarget.Length;
    if((FindTargetLength-1)<FindItemLength) return -1;

    for(int i=FindTargetLength-FindItemLength-1;i>-1;i--)
    {
     System.Collections.ArrayList tmpList=new System.Collections.ArrayList();
     int find=0;
     for(int j=0;j<FindItemLength;j++)
     {
      if(FindTarget[i+j]==FindItem[j]) find+=1;
     }
     if(find==FindItemLength)
     {
      index=i;
      break;
     }
    }
    return index;
   }