.net上传Excel，解析Excel，导出CSV

 　 //上传
　　protected void btnUpload_Click(object sender, EventArgs e)
    {
        string filePath = Server.MapPath("~/UploadFile");
        if (fileUploadDatas.HasFile)
        {
            filePath =filePath + Guid.NewGuid().ToString("N") + Path.GetExtension(fileUploadDatas.FileName);
            fileUploadDatas.SaveAs(filePath);
            DataTable dt = ReadExcelToTable(filePath);
        }
    }
　　 //读取Excel到DataTable
    private DataTable ReadExcelToTable(string path)
    {
        string connstring = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties='Excel 8.0;HDR=NO;IMEX=1';";   // Office 07,10
        //string connstring = Provider=Microsoft.JET.OLEDB.4.0;Data Source=" + path + ";Extended Properties='Excel 8.0;HDR=NO;IMEX=1';";  //Office 03
        using (OleDbConnection conn = new OleDbConnection(connstring))
        {
            conn.Open();
            DataTable sheetsName = conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new object[] { null, null, null, "Table" });
            //string firstSheetName = sheetsName.Rows[0][2].ToString();     
            try
            {
                string sql = string.Format("SELECT * FROM [{0}]", "Template$");//firstSheetName);      
                OleDbDataAdapter ada = new OleDbDataAdapter(sql, connstring);
                DataSet set = new DataSet();
                ada.Fill(set);
                return set.Tables[0];
            }
            catch
            {
                return new DataTable();
            }
        }
    }
　　 //导出CSV的方法
    public void ExportToCSV(string[] list)
    {
        string temp = string.Format("attachment;filename={0}", DateTime.Now.ToString("yyyyMMddHHmmss") + ".csv");
        Response.ClearHeaders();
        Response.AppendHeader("Content-disposition", temp);
        Response.ContentType = "application/unkown";
        Response.ContentEncoding = Encoding.UTF8;
        StreamWriter sw = new StreamWriter(Response.OutputStream, Encoding.Default);
        foreach (string item in list)
        {
            sw.WriteLine(item);
        }
        sw.Close();
        Response.End();
    }