/// <summary>

         /// 从LBS云端删除数据

         /// </summary>

         /// <param name="ak">百度密钥</param>

         /// <param name="geotable_id">LBS云geotableID</param>

         /// <param name="columnName">字段名称</param>

         /// <param name="columnValue">值(为空时则删除所有匹配的数据)</param>

         /// <returns></returns>

         public string DeleteByName(string ak, string geotable_id, string columnName, string columnValue)

         {

            string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");

             //请求

             WebRequest req = WebRequest.Create(@"http://api.map.baidu.com/geodata/v2/poi/delete");

             req.Method = "POST";

             req.ContentType = "multipart/form-data; boundary=" + boundary;

             //组织表单数据

             StringBuilder sb = new StringBuilder();

             sb.Append("--" + boundary);

             sb.Append("\r\n");

             sb.Append("Content-Disposition: form-data; name=\"ak\"");

             sb.Append("\r\n\r\n");

             sb.Append(ak);

             sb.Append("\r\n");

             sb.Append("--" + boundary);

             sb.Append("\r\n");

             sb.Append("Content-Disposition: form-data; name=\"geotable_id\"");

             sb.Append("\r\n\r\n");

             sb.Append(geotable_id);

             sb.Append("\r\n");

             sb.Append("--" + boundary);

             sb.Append("\r\n");

             sb.Append("Content-Disposition: form-data; name=\"" + columnName + "\"");

             sb.Append("\r\n\r\n");

             sb.Append(columnValue);

             sb.Append("\r\n");

             sb.Append("--" + boundary);

             sb.Append("\r\n");

             string head = sb.ToString();

             byte[] form_data = Encoding.UTF8.GetBytes(head);

             //结尾

             byte[] foot_data = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");

             //post总长度

             long length = form_data.Length +  foot_data.Length;

             req.ContentLength = length;

             Stream requestStream = req.GetRequestStream();

             //发送表单参数

             requestStream.Write(form_data, , form_data.Length);

             //结尾

             requestStream.Write(foot_data, , foot_data.Length);

             requestStream.Close();

             //响应

             WebResponse pos = req.GetResponse();

             StreamReader sr = new StreamReader(pos.GetResponseStream(), Encoding.UTF8);

             string html = sr.ReadToEnd().Trim();

             sr.Close();

             if (pos != null)

             {

                 pos.Close();

                 pos = null;

             }

             if (req != null)

             {

                 req = null;

             }

             return html;

         }

   /// <summary>

         /// 模拟表单提交，实现提交csv格式文件的上传

         /// </summary>

         /// <param name="ak"></param>

         /// <param name="geotable_id"></param>

         /// <param name="file"></param>

         /// <returns></returns>

         public string UploadCSVFile(string ak, string geotable_id, string filePath)

         {

             string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");

             //请求

             WebRequest req = WebRequest.Create(@"http://api.map.baidu.com/geodata/v2/poi/upload");

             req.Method = "POST";

             req.ContentType = "multipart/form-data; boundary=" + boundary;

             //组织表单数据

             StringBuilder sb = new StringBuilder();

             sb.Append("--" + boundary);

             sb.Append("\r\n");

             sb.Append("Content-Disposition: form-data; name=\"ak\"");

             sb.Append("\r\n\r\n");

             sb.Append(ak);

             sb.Append("\r\n");

             sb.Append("--" + boundary);

             sb.Append("\r\n");

             sb.Append("Content-Disposition: form-data; name=\"geotable_id\"");

             sb.Append("\r\n\r\n");

             sb.Append(geotable_id);

             sb.Append("\r\n");

             sb.Append("--" + boundary);

             sb.Append("\r\n");

             sb.Append("Content-Disposition: form-data; name=\"poi_list\"; filename=\"e:\\databox.csv\"");

             sb.Append("\r\n");

             sb.Append("Content-Type: application/octet-stream");

             sb.Append("\r\n\r\n");

             string head = sb.ToString();

             byte[] form_data = Encoding.UTF8.GetBytes(head);

             //结尾

             byte[] foot_data = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");

             //文件

             FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);

             //post总长度

             long length = form_data.Length + fileStream.Length + foot_data.Length;

             req.ContentLength = length;

             Stream requestStream = req.GetRequestStream();

             //发送表单参数

             requestStream.Write(form_data, , form_data.Length);

             //文件内容

             byte[] buffer = new Byte[checked((uint)Math.Min(, (int)fileStream.Length))];

             int bytesRead = ;

             while ((bytesRead = fileStream.Read(buffer, , buffer.Length)) != )

                 requestStream.Write(buffer, , bytesRead);

             //结尾

             requestStream.Write(foot_data, , foot_data.Length);

             requestStream.Close();

             //响应

             WebResponse pos = req.GetResponse();

             StreamReader sr = new StreamReader(pos.GetResponseStream(), Encoding.UTF8);

             string html = sr.ReadToEnd().Trim();

             sr.Close();

             if (pos != null)

             {

                 pos.Close();

                 pos = null;

             }

             if (req != null)

             {

                 req = null;

             }

             return html;

         }