c# - How do i dynamically cast a child class from its parent class? -

What I'm trying to do here is that I have a class with the parentform one of its essentials Form has been added to the class with 2 things.

Then every and form I get it near ParentForm so I like

  class f1 : Parentform class F2: ParentForm class f3: ParentForm etc ...   
 Now I say that I have both  F1  and  F2  A button is  F3  and the  F3  form constructor looks like this:  
  public parent (parent parent parent)  < / Pre> 
 I use the variables back to the original form (in this case either  F1  or  F2 ) to add data to lists or everything else  
 Now here's my problem. I'm talking like this for now:  
  if (parent.GetType () == typeof (f1)) {((f1) parent) .list.Add ("A"); } And if (Parents getType () == Type (f2)) {((2) parent) .list.Add ("a"); }   
 So I am making a check for every parent, how can I do this dynamically? Some such  
  (parent.GetType () parent) .list.Add ("a");   
 But most of it does not work Has anyone got the solution?   
 
 
 I'm not sure that this is the best solution, but I How to do this:  
  Abstract class ParentForm {... public abstract void update  (T updateValue)} public class f1: ParentForm {... private list & lt ; String & gt; List; Public override zero update (string value) {list.Add (value);}} Public F2: ParentForm {.... Private list & lt; int & gt; list; public override zero updates {int} {...}}   
 and so on