How to call methods of another Form from child window

hey,

refer this

 

1.http://stackoverflow.com/questions/16818925/c-sharp-call-a-function-in-a-parent-form

2.http://stackoverflow.com/questions/22218118/how-to-call-parent-form-method-from-child-form-in-c

3.https://social.msdn.microsoft.com/Forums/windows/en-US/bf412be3-7091-4c26-9a70-bd90eeb03e43/how-to-call-method-for-the-active-child-form-in-c-from-the-parent-window-toolstrip?forum=winforms