I need to update a ListBox of a Form2 created dinamically. Let's say that in the event where I have to update this ListBox (in Form1 of course) I don't have a reference of this Form2 so I can't call the UpdateList method (and no, I can't make it static). I don't even know if there is a Form2 opened, it could be or not. What do you suggest? Is there a way to loop through all the open istances of Form2? Code Sample: //Form1 public void event() { //UPDATE FORM2 LISTBOX } //SOMEWHERE IN FORM1 Form2 runTime = new Form2(); //Form2 public void UpdateList() { //UPDATE LISTBOX }