c# - Navigating from Page/ Page Function to PageFunction Null Reference Exception occurs -

page.cs

private void pagebutton_click(object sender, routedeventargs e) {     pagefunction pagefunction = new pagefunction();     pagefunction.return += new returneventhandler<string>(pagefunction_return);     this.navigationservice.navigate(pagefunction); }  static void pagefunction_return(object sender, system.windows.navigation.returneventargs<string> e) {     string returnedvaule = e.result;     messagebox.show(returnedvaule); } 

pagefunction.cs

private void pagefunctionbutton_click(object sender, routedeventargs e) {     onreturn(new returneventargs<string>("returned")); } 

as shown above have page , pagefunction.

on pagebutton_click of page.cs, navigating pagefunction, after execution of whole pagebutton_click event, null reference exception (i.e, object reference not set instance of object).

and dont know why exception ocurred.

help me out problem.

thanks.

remember -> pagefunction<string> may you.