c# - Caliburn.Micro attach event handler on event of Behavior -

i wrote own behavior handle swipe gesture , put itemtemplate of listview. if swipe completed, raise event leftswipe or rightswipe. event should handled viewmodel.

i use syntax of caliburn.micro attach handler event: cm:message.attach="[event leftswipe] = [leftswipe($source, $eventargs)".

this behavior:

public class swipeinteractionbehavior : dependencyobject, ibehavior {     public dependencyobject associatedobject { get; private set; }      public void attach(dependencyobject associatedobject)     {         // ...     }      public void detach()     {         // ...     }      public event eventhandler leftswipe;      public event eventhandler rightswipe;      // ...     // ...      private void onleftswipe(frameworkelement element)     {         // ...          if (leftswipe != null)         {             leftswipe(this, eventargs.empty);         }     }      private void onrightswipe(frameworkelement element)     {         // ...         if (rightswipe != null)         {             rightswipe(this, eventargs.empty);         }      } } 

this how use behavior inside of listviews itemtemplate:

        <listview x:name="links" isitemclickenabled="true" selectionmode="none" cm:message.attach="[event itemclick] = [click($source, $eventargs)]">             <listview.itemtemplate>                 <datatemplate>                     <grid>                         <grid>                             <border x:name="todoitem" loaded="border_loaded" background="white">                                 <i:interaction.behaviors>                                     <local:swipeinteractionbehavior cm:message.attach="[event leftswipe] = [leftswipe($source, $eventargs)]" />                                 </i:interaction.behaviors>                                  <grid>                                     <stackpanel>                                         <textblock text="{binding title}" style="{themeresource listviewitemcontenttextblockstyle}" />                                         <textblock text="{binding url}" style="{themeresource listviewitemsubheadertextblockstyle}" />                                         <textblock text="{binding tags, converter={staticresource listtostring}}" />                                     </stackpanel>                                 </grid>                             </border>                         </grid>                     </grid>                 </datatemplate>             </listview.itemtemplate>         </listview> 

i ran in exception if raise leftswipe event, stacktrace:

system.exception not handled.   hresult=-2146233088   message=no target found method leftswipe.   source=caliburn.micro.platform   stacktrace:        @ caliburn.micro.actionmessage.invoke(object eventargs)        @ caliburn.micro.triggeraction`1.execute(object sender, object parameter)        @ microsoft.xaml.interactivity.interaction.executeactions(object sender, actioncollection actions, object parameter)        @ microsoft.xaml.interactions.core.eventtriggerbehavior.onevent(object sender, object eventargs)        @ readerapp.swipeinteractionbehavior.<>c__displayclass5.<onleftswipe>b__4()        @ readerapp.extensions.frameworkelementextension.<>c__displayclass2.<animate>b__0(object s, object e)   innerexception:  

viewmodel:

public class mainviewmodel : viewmodelbase {     private readonly ieventaggregator eventaggregator;     private readonly database database;      public bindablecollection<link> links     {         get;         private set;     }      public mainviewmodel(inavigationservice navigationservice, ieventaggregator eventaggregator, database database)         : base(navigationservice)     {         this.eventaggregator = eventaggregator;         this.database = database;          links = new bindablecollection<link>();     }      public async void leftswipe(object sender, eventargs e)     {         // ...     }      public void rightswipe(object sender, eventargs e)     {         // ...     } } 

so problem actionmessage inherits triggeraction<frameworkelement> means can't attach correctly swipeinteractionbehavior.

it's complicated fact there's major api differences between wpf / silverlight / windows phone 8 interactivity sdk , winrt interactivity sdk. can see bit of mean in parser comments.

what i'd recommend implementing swipeinteractionbehavior trigger behaviour eventtriggerbehavior, used separate base class winrt it's still ibehavior, difference has property called actions of type actioncollection. stupidly there no interface base class enforcing caliburn.micro stuck making assumptions.

you'd use interaction.executeactions trigger actions, in end xaml should like.

<border x:name="swipetarget">   <i:interaction.behaviors>     <local:swipeeventbehavior direction="left">       <cm:actionmessage associatedobject="{binding elementname=swipetarget" method="leftswipe" />     </local:swipeeventbehavior>   </i:interaction.behaviors> </border> 

it's bit more long winded, need work around limitations imposed changes in sdk.