DropDown with bound ObservableCollection

Radzen.Blazor Components
1

I have a dropdown configured as part of a foreach loop (so there will be a variable number of these configured). I have each one bound to an ObservableCollection which is a member of a dictionary. This part all works correctly, the collection in the dictionary is updated correctly.
The issue is that when I add an EventHandler to the collection, it is never fired. I've downloaded the source code for the drop down and added to my project to step into it, and I think the issue is that the DropDown creates a new collection and replaces the existing collection in my dictionary, thus removing the eventhandler (or bypassing it). I believe this happens on line 1137 of DropDownBase.cs.
This is how I've configured the DropDown:

<Radzen.Blazor.RadzenDropDown TValue="ObservableCollection<CategoryScore>"
							@bind-Value=@(Scores[sport])
							Data=@category.Scores
							id=@sport.Id
							AllowSelectAll="false"
							Multiple="true"
							Chips="true"
							TextProperty="Name"
							Change=@(scores => ScoreSelectionOnChange( scores, sport)) />

The scores object is configured as:

private readonly Dictionary<CategorySport, ObservableCollection<CategoryScore>> Scores = [];

Is there any way to work around this issue?

2

Blazor two-way bindings will expect exactly this, they don't work with INotifyCollectionChanged but will raise the property setter of the property.

3

Thanks Enchev.

I have been able to work around this by using the Change method, but that gives me a full list which I then have to compare against what is in my base object to work out what is removed. The base object does not expose a list of scores, but has functions to add and remove them, hence why I wanted the change tracking.

I was hoping the DropDown would use the add and remove functions (if available) rather than just assigning a new list (especially considering when using multiple selections, only one object would be added or removed at a time).