Extending a provided class
<p>I have extended a class like so:</p>

<pre><code>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()
    {
    }
}
</code></pre>

<p>I am now trying to adjust some code elsewhere to accommodate this update.</p>

<p>The old code was this:</p>

<pre><code>List&lt;RadDock&gt; docks = new List&lt;RadDock&gt;(dockLayout.RegisteredDocks);
</code></pre>

<p>where RegisteredDocks is of type <code>"System.Collections.ObjectModel.ReadOnlyCollection&lt;RadDock&gt;"</code></p>

<p>I do not understand why this is not possible:</p>

<pre><code>List&lt;CormantRadDock&gt; docks = new List&lt;CormantRadDock&gt;(dockLayout.RegisteredDocks);
</code></pre>

<p>I receive the errors: </p>

<p>The best overloaded method match for 'System.Collections.Generic.List.List(System.Collections.Generic.IEnumerable)' has some invalid arguments.</p>

<p>Argument 1: cannot convert from 'System.Collections.ObjectModel.ReadOnlyCollection' to 'System.Collections.Generic.IEnumerable'   </p>

<p>Could someone please explain why this is occurring and a best possible solution?</p>
