c# - uwp c# pass additional parameter to an navigationview event handler while binding the event at runtime

Question

I have a navigationview and I want to pass extra argument to selection_changed event

MUXC.NavigationView navigationview = new MUXC.NavigationView();
navigationview.SelectionChanged += new EventHandler((s, e) => Navigationview_SelectionChanged(s, e, param));

getting error for above code

Cannot implicitly convert type 'System.Eventhandler' to 'Windows.Foundation.TypedEventHandler'

标签： c#uwpevent-handlingarguments

Answer 1

When attaching events, there is usually no need to new an EventHandler, because the type of NavigationView.SelectionChanged is TypedEventHandler, direct assignment will cause the type to mismatch.

If you create a SelectionChanged event handle method, you can attach it like this:

var navigationview = new muxc.NavigationView();
navigationview.SelectionChanged += Navigationview_SelectionChanged;

private void Navigationview_SelectionChanged(muxc.NavigationView sender, muxc.NavigationViewSelectionChangedEventArgs args)
{
    // Do something...
}

From your code, you seem to have created a method with three parameters. If you need to keep the param, then you need to perform some conversion.

navigationview.SelectionChanged += (_s, _e) =>
{
    Navigationview_SelectionChanged(_s, _e, param);
};