c# - InvalidComObjectException when using GeckoWebBrowser -

i using geckowebbrowser geckofx45 extract source of webpage after loaded.

when running code once works fine, when run multiple times invalidcomobjectexceptionis thrown:

system.runtime.interopservices.invalidcomobjectexception: 'com object has been separated underlying rcw cannot used.'

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code:

public static async task<string> loaddomsourceasync(string url, cancellationtoken cancellationtoken) {     using (var apartment = new messageloopapartment())         return await apartment.run(async () => {             using (var wb = new geckowebbrowser()) {                 var tcs = new taskcompletionsource<string>();                 try {                     wb.documentcompleted += (s, a) => tcs.trysetresult(((geckohtmlhtmlelement)wb.document.documentelement).outerhtml);                     wb.navigationerror += (s, a) => tcs.trysetexception(new geckonetworkexception());                     wb.navigate(url);                     return await tcs.task;                 } catch (exception e) { tcs.trysetexception(e); }                 {                     wb.stop();                 }                 return null;             }         }, cancellationtoken); } 

messageloopapartment:

using system; using system.linq; using system.threading; using system.threading.tasks; using system.windows.forms;  namespace streamlinkextract {     /// <summary>     /// messageloopapartment     /// sta thread message pump serial execution of tasks     /// noseratio - http://stackoverflow.com/a/22262976/1768303     /// </summary>     public class messageloopapartment : idisposable {         thread _thread; // sta thread          taskscheduler _taskscheduler; // sta thread's task scheduler          public taskscheduler taskscheduler { { return _taskscheduler; } }          /// <summary>messageloopapartment constructor</summary>         public messageloopapartment() {             var tcs = new taskcompletionsource<taskscheduler>();              // start sta thread , gets task scheduler             _thread = new thread(startarg => {                 eventhandler idlehandler = null;                  idlehandler = (s, e) => {                     // handle application.idle once                     application.idle -= idlehandler;                     // return task scheduler                     tcs.setresult(taskscheduler.fromcurrentsynchronizationcontext());                 };                  // handle application.idle once                 // make sure we're inside message loop                 // , synchronizationcontext has been correctly installed                 application.idle += idlehandler;                 application.run();             });              _thread.setapartmentstate(apartmentstate.sta);             _thread.isbackground = true;             _thread.start();             _taskscheduler = tcs.task.result;         }          /// <summary>shutdown sta thread</summary>         public void dispose() {             if (_taskscheduler != null) {                 var taskscheduler = _taskscheduler;                 _taskscheduler = null;                  // execute application.exitthread() on sta thread                 task.factory.startnew(                     () => application.exitthread(),                     cancellationtoken.none,                     taskcreationoptions.none,                     taskscheduler).wait();                  _thread.join();                 _thread = null;             }         }          /// <summary>task.factory.startnew wrappers</summary>         public void invoke(action action) {             task.factory.startnew(action,                 cancellationtoken.none, taskcreationoptions.none, _taskscheduler).wait();         }          public tresult invoke<tresult>(func<tresult> action) {             return task.factory.startnew(action,                 cancellationtoken.none, taskcreationoptions.none, _taskscheduler).result;         }          public task run(action action, cancellationtoken token) {             return task.factory.startnew(action, token, taskcreationoptions.none, _taskscheduler);         }          public task<tresult> run<tresult>(func<tresult> action, cancellationtoken token) {             return task.factory.startnew(action, token, taskcreationoptions.none, _taskscheduler);         }          public task run(func<task> action, cancellationtoken token) {             return task.factory.startnew(action, token, taskcreationoptions.none, _taskscheduler).unwrap();         }          public task<tresult> run<tresult>(func<task<tresult>> action, cancellationtoken token) {             return task.factory.startnew(action, token, taskcreationoptions.none, _taskscheduler).unwrap();         }     } }