c# - WPF TreeView does not pick up templates, calls ToString() instead -

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• how bind datatemplate datatype interface? 1 answer

i have in xaml:

<treeview datacontext="{binding source={staticresource locator}}" itemssource="{binding sometree.toplevelitems}">     <treeview.resources>         <datatemplate datatype="{x:type vm:ileaf}">             <checkbox content="{binding name}" isthreestate="false" ischecked="{binding isenabled, mode=twoway, updatesourcetrigger=propertychanged}" />         </datatemplate>         <hierarchicaldatatemplate datatype="{x:type vm:igroup}" itemssource="{binding children}">             <checkbox content="{binding name}" isthreestate="true" ischecked="{binding isenabled, mode=twoway, updatesourcetrigger=propertychanged}" />         </hierarchicaldatatemplate>     </treeview.resources> </treeview> 

vm: defined accordingly:

xmlns:vm="clr-namespace:my.viewmodels.mytree" 

and mytree namespace contains interfacesigroup , ileaf.

the sometree.toplevelitems enumerable of igroups , ileafs (it populated dynamically).

now, treeview should display tree of checkboxes accordingly, displaying top-level elements of items source, not applying data template, , calls tostring() on elements instead.

the other post mentions same problem not apply here, checked that.

what missing / doing wrong?

templates work off concrete classes not interfaces,

this feature if have 2 interfaces on 1 class template should select?

as system can't know not allowed it

see full ms response here https://social.msdn.microsoft.com/forums/vstudio/en-us/1e774a24-0deb-4acd-a719-32abd847041d/data-templates-and-interfaces?forum=wpf

instead use datatemplateselector rather type up, way can tell system how interpret multi interface situation

public class tasklistdatatemplateselector : datatemplateselector {     public override datatemplate         selecttemplate(object item, dependencyobject container)     {         frameworkelement element = container frameworkelement;          if (element != null && item != null && item task)         {             task taskitem = item task;              if (taskitem.priority == 1)                 return                     element.findresource("importanttasktemplate") datatemplate;             else                 return                     element.findresource("mytasktemplate") datatemplate;         }          return null;     } }