Export data Using ADO

December 2015, XX project need to do a data export function, at that time all the functions of the page everywhere has been implemented, but there is a large amount of page data, export the process of exporting the page directly to die. I have to choose to use ADO to re-complete this function, because the more inclined to the bottom of the logic, I choose to read directly from the SqlCommand data, every 20,000 data write a file, to avoid writing too many pages at once to die, the final test can export 25G of data to meet the system requirements.

usingSystem;usingSystem.Data;usingSystem.Data.SqlClient; Public classado_net{ PublicActionResult ExportData () {stringSabsolutepath ="XXX"; stringFileName =string. Format ("Aq_{0}.csv", DateTime.Now.ToString ("YYYYMMDDHHMMSS")); Try{Fincapdbcontext db=Dbcontextfactory.getcurrentcontext (); SqlConnection Conn=NewSqlConnection (db.            currentconnectionstring); Conn.            Open (); SqlCommand cmd=NewSqlCommand ("SQL Statement", conn); Cmd.commandtimeout= -; SqlDataReader SDR=cmd.            ExecuteReader (); StreamWriter SW=NewStreamWriter (Sabsolutepath +"\\"+ FileName,false, Encoding.GetEncoding ("GB2312")); StringBuilder SB=NewStringBuilder (); intK =0;  for(intm =0; M < SDR. FieldCount; m++) {sb. Append (SDR). GetName (m)+","); } sb.            Append (Environment.NewLine);  while(SDR). Read ()) {k++;  for(intn =0; N < SDR. FieldCount; n++) {sb. Append (Sdr[n]+","); } sb.                Append (Environment.NewLine); if(k >20000) {k=0; Sw. Write (sb.)                    ToString ()); Sb. Length=0; }            }            if(k <=20000) {SW. Write (sb.)            ToString ()); } SW.            Flush (); Sw.            Close (); Conn.            Close (); returnFile (Sabsolutepath +"\\"+ FileName,"application/zip-x-compressed", FileName); }        Catch        {            returnFile ("XXX"); }    }}

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Export data Using ADO