What is the namespace of Get/SetPropertyValue in Extender Implementation

Question

I'm creating an extender control by referring this article, but I'm facing hard time to get/know the namespace of GetPropertyValue and SetPropertyValue which used in the example like this:

    [ExtenderControlProperty]
    public string DragItemHandleClass
    {
        get
        {
            return GetPropertyValue<String>("DragItemHandleClass", string.Empty);
        }
        set
        {
            SetPropertyValue<String>("DragItemHandleClass", value);
        }
    }

I observed this on other sites too, so its not a custom implementation and I couldn't find it on AjaxControlToolkit. Could some one please guide me on this?

Answer 1

The ExtenderControlBase provides implementation for these generic methods. Hence, deriving your extender from it resolves the issue here.