Querying the ASP.NET form object with linq

Question

Is it possible to select all controls that inherit a particular abstract class with linq.

Answer 1

Make use of the Enumerable.OfType<T> extension method:

...Form.Controls.OfType<MyControlBase>()...

To perform this recursively see the other answer: create an iterator that walks the control tree to create a list which you then apply LINQ operators to.

Answer 2

Assuming you have a method which recursively gets all the controls, as follows:

public static IEnumerable<Control> GetControls(Control form) {
    foreach (Control childControl in form.Controls) {   // Recurse child controls.
        foreach (Control grandChild in GetControls(childControl)) {
            yield return grandChild;
        }
        yield return childControl;
    }
}

Then you can do:

var controls = GetControls(form).OfType<SomeControlBase>();