WinForms IBindingList Collection Support

[bchavez]

Hello,

ReactiveUI has deprecated ReactiveBindingList<T> which had support for IBindingList. The obsolete message reads:

ReactiveList is no longer supported. We suggest replacing
it with DynamicData https://github.com/rolandpheasant/dynamicdata

So I searched here for any type that implements IBindingList and couldn't find anything. Effectively, without some type implementing IBindingList there doesn't seem to be a story for binding collections to WinForms controls such as a ListBox.

I think what we need is a type similar to WPF's ObservableCollectionExtended<T>, but for WinForms like ObservableBindingListExtended<T> that implements IBindingList (or BindingList<T>) that can be used similar to:

this.SourceCache
   .Connect()
   .Bind(this.ObservableBindingListExtended)
   .Subscribe();

Let me know your thoughts.

Thanks,
Brian

[glennawatson]

@RolandPheasant You should actually be able to make a ReadOnlyBindableCollection<T> style container and use the Bind(out myList); type syntax.

[RolandPheasant]

Hi, I agree this needs adding to the lib.

In the meantime there is a sample implementation which you can copy into your project binding list example

[RolandPheasant]

The example in the link is for a list, not a cache. I will ensure both list and cache are supported. Also I will post a cache example later so you can test it before release.

[RolandPheasant]

I have added Bind() support for binding list for both cache and list parts of the system.

What I have not done is to support ToObservableChangeSet() from BindingList.

Also the suggestion by @glennawatson to create a read-only binding list and bind using an out param is not implemented. I will probably do it in the near future.

@bchavez since this is new functionality I could deploy to Nuget without breaking any code so I will do this very soon. However it would be good if you can download the packages from here AppVeyor Build v99.99.99.2523-branches and test first

[RolandPheasant]

@bchavez I've merge it in, so you need to download v6.7.0 from the AppVeyor artefacts

[bchavez]

Hey @RolandPheasant ,

I think it works!

Thanks again so much for your help @RolandPheasant and @glennawatson . Such amazing work! I really appreciate it.

BTW, here is my ViewModel code in case anyone is interested:

public class Account
{
   public int Id { get; set; }
   public string Name { get; set; }
   public string Number { get; set; }
}

public class MainViewModel : ReactiveObject
{
   public MainViewModel()
   {
      this.Accounts = new BindingList<Account>();
      this.AccountCache = new SourceCache<Account, int>(f => f.Id);


      this.AccountCache.Connect()
         .Bind(this.Accounts)
         .Subscribe();

      var hasAccounts = this.AccountCache.CountChanged
         .Select(x => x > 0);
      
      this.AddAccount = ReactiveCommand2.Create(AddAccountImpl, Observable.Return(true));
      this.RemoveAccount = ReactiveCommand2.Create(RemoveAccountImpl, hasAccounts);
   }

   private Account selectedAccount;
   public Account SelectedAccount
   {
      get => selectedAccount;
      set => this.RaiseAndSetIfChanged(ref selectedAccount, value);
   }

   public ReactiveCommand2<Unit, Unit> AddAccount { get; }
   public ReactiveCommand2<Unit, Unit> RemoveAccount { get; }

   public BindingList<Account> Accounts { get; }

   public SourceCache<Account, int> AccountCache { get; }

   private void RemoveAccountImpl()
   {
      if( this.selectedAccount != null )
         this.AccountCache.Remove(this.selectedAccount);
   }

   private int nextId = 0;

   private void AddAccountImpl()
   {
      var id = nextId++;
      var a = new Account
         {
            Id = id,
            Name = $"Account {id}",
            Number = "12345"
         };

      this.AccountCache.AddOrUpdate(a);
   }
}

I hope I'm using the new IBindingList feature correctly. I'm very noobish with ReactiveUI; I'm still learning! 😢

[RolandPheasant]

That's great to see. I will deploy it now.

Are you on slack? There is an active community with channels for Rx, RxUI and DynamicData. It is a great place to ask questions Link to join slack

[RolandPheasant]

On second thoughts it is late here and I need to update the release notes before I deploy. Will do it in the next couple days.

[bchavez]

@RolandPheasant , yep! Just joined slack yesterday my username is @bchavez. It was @glennawatson on slack who suggested I raise the issue about IBindingList here. :)

Again, thanks for all the help and support! ❤️ I have a long road ahead to learn all the ins and outs, but this IBindingList was a major blocker that's now been unblocked. :)

[RolandPheasant]

Feel free to ask any questions and report any issues

[RolandPheasant]

Fixed by PR #183