> how you're supposed to properly update data for a grouped List/GridView without causing the entire view to rerender
By telling your views what was updated.
For updating sets of items, see INotifyCollectionChanged interface, implemented by ObservableCollection<T> from the framework.
For updating properties, see INotifyPropertyChanged.
> Multiple components got kind of close, but always lacked 1 aspect
Find a panel that does it best, then either copy-paste and patch, or inherit and override.
The entire layout model is implemented in just 2 methods, MeasureOverride and ArrangeOverride. They are virtual, i.e. designed to be user-replaceable as you inherit from framework classes.
By telling your views what was updated.
For updating sets of items, see INotifyCollectionChanged interface, implemented by ObservableCollection<T> from the framework.
For updating properties, see INotifyPropertyChanged.
> Multiple components got kind of close, but always lacked 1 aspect
Find a panel that does it best, then either copy-paste and patch, or inherit and override.
The entire layout model is implemented in just 2 methods, MeasureOverride and ArrangeOverride. They are virtual, i.e. designed to be user-replaceable as you inherit from framework classes.