c# - Cannot access a disposed object. Asynchronous print of messages in second form -

asynchronous print of messages in second form. system.objectdisposedexception in system.windows.forms.dll during close of second form.

mainform runs secondform. secondform runs message generator , asynchronous thread of print of messages in text box. message generator creates messages random time delay. time delay in string format message. problem - during close of second form, method secondform_closing, receive exception

system.objectdisposedexception in system.windows.forms.dll during cannot access disposed object.

public partial class mainform : form {     secondform secondform;     private void mainform_closing(object o, formclosingeventargs e)     {         environment.exit(0);     }     public mainform()     {         initializecomponent();         secondform = new secondform();         secondform.show();     } } public partial class secondform : form {     private messagegenerator messagegenerator;     action actprint;     //this method calls objectdisposedexception point invoke in method print     private void secondform_closing(object o, formclosingeventargs e)     {         close();     }     public secondform()     {         initializecomponent();         messagegenerator = new messagegenerator();         actprint = new action(print);         actprint.begininvoke(null, null);     }     public void print()     {         while (true)   //  infinite  cycle         {             messagegenerator.createevent.waitone(); //  wait event "message created"             messagegenerator.createevent.reset();//  event reset             invoke(new methodinvoker             (() =>             {                 textboxtimedelay.text = messagegenerator.message;//  message print             }));         }     } } public class messagegenerator {     public autoresetevent createevent;     public string message;     public action actstart;     public messagegenerator()     {         createevent = new autoresetevent(false);         actstart = new action(start);         actstart.begininvoke(null, null);     }     public void start()     {         random r = new random();         while (true)         {             int timedelay = 10 * r.next(1, 5);             thread.sleep(timedelay);             message = timedelay.tostring();             createevent.set();  //  event "message created"         }     } } 

solution here not realizes of resources. i.e. messagegenerator continued, , print method worked. how realizes resources ?

private void secondform_closing (object o, formclosingeventargs e) {     e.cancel = true;     this.hide();     this.parent = null; }