c# - Async and Await : Error In MVC -

hi have problem use async , wait in following method. used neevia converter convert document , want wait method until conversion completed.

could please help:

public void asyncandwaittillexecutionmethod(string filename) {       callforconverter(filename);     }      private async void callforconverter(string filename) {         var result = await callforconverterasync(filename);     }      private task<string> callforconverterasync(string filename) {         string fromlocation;         string tolocation;          //  data source         string filefullname = filename;         fromlocation = "abc";          tolocation = "xyz";         return task.factory.startnew(() => convertusingneevia(fromlocation, tolocation));      }     private string convertusingneevia(string from, string to) {         string success = "false";          int timeout = 3000;         try {             neevia.docconverter nvdc = new neevia.docconverter();             int res = nvdc.convertfile(from, to, timeout);         }         catch (exception ex) {             throw new exception("exception ", ex);         }         success = "true";         return success;      }  

it giving me following error callforconverter() method. asynchronous operation cannot started @ time. asynchronous operations may started within asynchronous handler or module or during events in page lifecycle in mvc...

just remove async, await, , (the horrible) startnew code:

public void asyncandwaittillexecutionmethod(string filename) {     string fromlocation;     string tolocation;      //  data source     string filefullname = filename;     fromlocation = "abc";      tolocation = "xyz";     convertusingneevia(fromlocation, tolocation); }