It is possible to subscribe to events with anonymous delegates, but having done so, it is impossible to unsubscribe from them. That's because the process of subscribing adds the delegate to a list. The process of unsubscribing essentially says: remove _this item_ from the subscription list. But because an anonymous delegate was used in both cases, the unsubscribe attempt tries to remove a different item from the list than was added. The result: ``++NOOP++``.


Instead, save the delegate to a variable and use the variable to subscribe and unsubscribe.


== Noncompliant Code Example

----
listView.PreviewTextInput += (obj,args) =>
        listView_PreviewTextInput(obj,args,listView);  

// ...

listView.PreviewTextInput -= (obj, args) => 
        listView_PreviewTextInput(obj, args, listView); // Noncompliant; this delegate was never subscribed
----


== Compliant Solution

----
EventHandler func = (obj,args) => listView_PreviewTextInput(obj,args,listView);

listView.PreviewTextInput += func;

// ...

listView.PreviewTextInput -= func;
----

