wpf - Adding custom/existing FrameworkElements to ItemsControl -

when add overridden frameworkelement or existing ui control itemscontrol, following binding error.

system.windows.data error: 25 : itemtemplate , itemtemplateselector not valid item.; type='button' system.windows.data error: 25 : itemtemplate , itemtemplateselector not valid item.; type='frameworkelement'

how should handling mixed uielement/non uielement types itemscontrol?

namespace wpfapplication27 {     class data     {         public string type { get; set; }     };      public partial class mainwindow : window     {         public mainwindow()         {             initializecomponent();              m_itemscontrol.items.add(new data() { type = "a" });             m_itemscontrol.items.add(new data() { type = "b" });             m_itemscontrol.items.add(new data() { type = "a" });             m_itemscontrol.items.add(new button());             m_itemscontrol.items.add(new frameworkelement());         }     }      public class customdatatemplateselector : datatemplateselector     {         public override datatemplate selecttemplate(object _item, dependencyobject _container)         {             var container = _container frameworkelement;             var data = _item data;              if (data.type == "a")             {                 return container.findresource("adatatemplate") datatemplate;             }             else if (data.type == "b")             {                 return container.findresource("bdatatemplate") datatemplate;             }              return null;         }     } }  <window x:class="wpfapplication27.mainwindow"     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"     xmlns:local="clr-namespace:wpfapplication27">  <window.resources>     <datatemplate x:key="adatatemplate">         <ellipse width="5" height="5" fill="red"/>     </datatemplate>      <datatemplate x:key="bdatatemplate">         <rectangle width="5" height="5" fill="blue"/>     </datatemplate>  </window.resources>      <itemscontrol name="m_itemscontrol">         <itemscontrol.itemtemplateselector>             <local:customdatatemplateselector/>         </itemscontrol.itemtemplateselector>          <itemscontrol.template>             <controltemplate>                 <canvas isitemshost="true"/>             </controltemplate>         </itemscontrol.template>     </itemscontrol> </window>