c# - WPF Binding in ComboBox with UserControl list -

in 2 combobox , b. a's itemssource custom list. , b's itemssource usercontrol list. when manually setting selecteditem, combobox works well, b combobox ui not show selected item. (in debugging, selecteditem's value mapping right, combobox b's ui not changed.) other structure same between , b. reason?

mainwindow.xaml

 ... <combobox itemssource="{binding fruitlist}" selecteditem="{binding selectedfruit}"   displaymemberpath="fruitname"  /> <button content="button" horizontalalignment="left"   verticalalignment="top" width="75" click="button_click"/>  <combobox itemssource="{binding usercontrollist}" selecteditem="{binding selectedusercontrol}" displaymemberpath="itemname"  />     <button content="button" horizontalalignment="left"  verticalalignment="top" width="75" click="button_click2"/> </grid> 

mainwindow.xaml.cs

public partial class mainwindow : window, inotifypropertychanged {     public mainwindow()     {         initializecomponent();         this.datacontext = this;          fruitlist.add(f1);         fruitlist.add(f2);         fruitlist.add(f3);          usercontrollist.add(u1);         usercontrollist.add(u2);         usercontrollist.add(u3);      }      fruit f1 = new fruit { fruitname = "apple" };     fruit f2 = new fruit { fruitname = "banana" };     fruit f3 = new fruit { fruitname = "lemon" };      myusercontrol u1 = new myusercontrol { itemname = "apple" };     myusercontrol u2 = new myusercontrol { itemname = "banana" };     myusercontrol u3 = new myusercontrol { itemname = "lemon" };      observablecollection<fruit> _fruitlist = new observablecollection<fruit>();     public observablecollection<fruit> fruitlist     {         { return _fruitlist; }         set         {             _fruitlist = value;             onpropertychanged();         }     }      fruit _selectedfruit;     public fruit selectedfruit     {         { return _selectedfruit; }         set         {             _selectedfruit = value;             onpropertychanged();         }     }        observablecollection<myusercontrol> _usercontrollist = new observablecollection<myusercontrol>();     public observablecollection<myusercontrol> usercontrollist     {                 {             return _usercontrollist;         }         set         {             _usercontrollist = value;             onpropertychanged();         }     }     myusercontrol _selectedusercontrol;     public myusercontrol selectedusercontrol     {         { return _selectedusercontrol; }         set         {             _selectedusercontrol = value;             onpropertychanged();         }     }      public event propertychangedeventhandler propertychanged;      void onpropertychanged([callermembername] string caller = "")     {         if (propertychanged != null)         {             propertychanged(this, new propertychangedeventargs(caller));         }     }       private void button_click(object sender, routedeventargs e)     {         this.selectedfruit = f3;     }      private void button_click2(object sender, routedeventargs e)     {         this.selectedusercontrol = u3;     } }  public class fruit {     public string fruitname { get; set; } } 

}

usercontrol

public partial class myusercontrol : usercontrol {     public myusercontrol()     {         initializecomponent();      }      public string itemname { get; set; } } 

this not way of achieving this. better define itemtemplate combobox have usercontrol in like:

  <combobox itemssource="{binding itemlist}" selecteditem="{binding selecteditem}" >         <combobox.itemtemplate>             <datatemplate>                 <mycontrols:myusercontrol/>             </datatemplate>         </combobox.itemtemplate>     </combobox> 

and define class item

public class item {     public string itemname { get; set; } }  observablecollection<item> _itemslist = new observablecollection<item>(); public observablecollection<item> itemslist  {         {         return _itemslist ;     }     set     {         _itemslist = value;         onpropertychanged();     } } 

here datacontext of usercontrol item object. can bind itemname within user control show in anyway want.

in user control can have:

 <textblock text="{binding itemname}"></textblock>