Help convert Control.ControlCollection => List<Control>

Question

Code Snippet

            //ArrayList controlList = new ArrayList(controlsContainer.Controls);

            List<Control> controlList = control.Controls as List<Control>;  // Conversion Error

            controlList.Sort(new ControlComparer());

In this situlation, how can I make a generic List<Control> from the a Control.ControlCollection ?

Answer 1

Is this .Net 3.5? Is so then this will work:

List<Control> controlList = new List<Control>();
controlList.AddRange(control.Controls.OfType<Control>();
controlList.Sort(new ControlComparer());

If not then you need to build the list:
List<Control> controlList = new List<Control>();
foreach(Control c in control.Controls)
{

controlList.Add(c);

}
controlList.Sort(new ControlComparer());

Answer 2

No. It is .NET 2.0

I use

Code Snippet

            List<Control> controlList = new List<Control>();

            foreach (Control ctrl in controlsContainer.Controls)

            {

                controlList.Add(ctrl);

            }

maybe there is an alternative?

Answer 3

Well control.Controls is of type ControllCollection which is IEnumerable, but not IEnumerable<Control>  so you cant just use add range.  The foreach is probably your best option if you want it in a List<Control>

If you just wanted to use ArrayList (since it takes anything) you could do:

ArrayList controlList = new ArrayList ();

controlList.AddRange(controlsContainer.Controls);

I think you are better off wiht the strongly types list and the foreach loop.

Answer 4

List<Control> controlList = new List<Control>(control.Controls.Cast<Control>());

Answer 5

Well control.Controls is of type ControllCollection which is IEnumerable, but not IEnumerable<Control>  ...

Given that, isn't the fastest and easiest way to just do:

controlsContainer.Controls.Cast<Control>().ToList();

The "Cast<Control>()" takes you from an IEnumerable to an IEnumerable<Control>, which is all that's necessary to open the door to LINQ magic (and by that I mean all your favorite extension methods in System.Linq.Enumerable :)

It's possibly slower, but it's declarative, which is always a plus.  Also, you can drop the ".ToList()" and do other IEnumerable LINQ operations at that point, such as Where, Select, OfType (OfType is often very useful with a list of Controls), etc etc.