Custom FindControl Implementation (C#) -- Part II

Part I of this topic dealt with overriding the basic FindControl method found native to objects inheriting from the System.Web.UI.Control object, which most people find severely lacking for uses other than simple pages/applications.

In this part, I will look at a simple extension from the recursive nature of the custom FindControl implementation that will allow us to find controls by another method: by type. Instead of searching for a single control by it’s string ID, we can scour any controls collection recursively for any controls which are of type X.

        public static ArrayList FindControls(Type type, ControlCollection col)
        {
            ArrayList list = new ArrayList();
            foreach(Control c in col)
            {
                if(c.GetType() == type)
                    list.Add(c);
                else
                    FindControlsRecursive(c, type, ref list);
            }
            return list;
        }

        private static void FindControlsRecursive(Control root, Type type, ref ArrayList list)
        {
            if(root.Controls.Count != 0)
            {
                foreach(Control c in root.Controls)
                {
                    if(c.GetType() == type)
                        list.Add(c);
                    else if (c.HasControls())
                        FindControlsRecursive(c, type, ref list);
                }
            }
        }

As you can see, the implementation of the recursive method is slightly different than the previous version for the single control. The only real difference is the presence of a by ref argument which is a data structure (in this case an ArrayList) to keep track of the results found.

About these ads