Question

I have extended a class like so:

public class CormantRadDock : Telerik.Web.UI.RadDock
{
    public enum Charts { LineChart, PieChart, BarChart };

    public Charts ChartType { get; set; }
    public bool LegendEnabled { get; set; }
    public string ChartName { get; set; }

    public CormantRadDock() : base()
    {
    }
}

I am now trying to adjust some code elsewhere to accommodate this update.

The old code was this:

List<RadDock> docks = new List<RadDock>(dockLayout.RegisteredDocks);

where RegisteredDocks is of type "System.Collections.ObjectModel.ReadOnlyCollection<RadDock>"

I do not understand why this is not possible:

List<CormantRadDock> docks = new List<CormantRadDock>(dockLayout.RegisteredDocks);

I receive the errors:

The best overloaded method match for ‘System.Collections.Generic.List.List(System.Collections.Generic.IEnumerable)’ has some invalid arguments.

Argument 1: cannot convert from ‘System.Collections.ObjectModel.ReadOnlyCollection’ to ‘System.Collections.Generic.IEnumerable’

Could someone please explain why this is occurring and a best possible solution?

Answer 1

Some of the RegisteredDocks might not be CormantRadDock, so they can’t be added to a List<CormantRadDock>.

If you’re only interested in the CormantRadDocks, you can filter by type:

List<CormantRadDock> docks = dockLayout.RegisteredDocks.OfType<CormantRadDock>().ToList();

If you know for sure that RegisteredDocks will only contain CormantRadDocks, you can cast each item:

List<CormantRadDock> docks = dockLayout.RegisteredDocks.Cast<CormantRadDock>().ToList();