Creating an instance of SelectionChangedEventArgs in wpf

4
votes

I have a user control which is having a listview inside it. The SelectionChanged event of this list view is handled inside the user control. The code for the same is as follows:

        private void lstvMyView_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {...}

I want to call this handler again from some other place inside the user control. So to call this handler i need the "SelectionChangedEventArgs" there. When I am trying to create the instance of "SelectionChangedEventArgs", i am unable to understand what should I pass as parameters to the constructor of "SelectionChangedEventArgs".

The place from where I am suppose to call this handler does not add or remove any items in the listview. It just navigates in the items in the listview thereby changing the selectedindex of the listview.

I am trying to do something like this. The below code is obviously incorrect.

lstvMyView_SelectionChanged(_lstvMyView, new SelectionChangedEventArgs());
2
wpfwpf-controls

2 Answers

2
votes

I want to call this handler again from some other place inside the user control

Don't. An event handler is not supposed to be called explicitly from your code. Whatever you're doing in this handler, you can put it in another method that only takes the parameters it needs, and call that method from your code.

2
votes

The SelectionChangedEventArgs can be instantiated for unit testing as follows:

new SelectionChangedEventArgs(
    System.Windows.Controls.Primitives.Selector.SelectionChangedEvent, 
    new List<CustomViewModel> { }, 
    new List<CustomViewModel> { customViewModel }
)

Beware that both the removedItems and addedItems cannot be null so an empty collection should be passed.