What class to inherit from for bound table source

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一个人的身影
一个人的身影 2021-02-01 11:21

I\'m using Xamarin and mvvmcross and what to have a view with a table ultimately bound to an observable collection.

This video is very informative on how to create cust

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  • 2021-02-01 11:59

    The available v3 table sources are:

    Abstract classes

    • MvxBaseTableViewSource
      • base functionality only
      • no ItemsSource - generally not used directly
    • MvxTableViewSource.cs
      • inherits from the basetable and addes ItemsSource for data-binding
      • inheriting classes need only to implement protected abstract UITableViewCell GetOrCreateCellFor(UITableView tableView, NSIndexPath indexPath, object item);

    Concrete classes

    • MvxStandardTableViewSource.cs
      • inherits from MvxTableViewSource
      • provides the 'standard iPhone cell types' via UITableViewCellStyle
      • within these you can bind TitleText, DetailText, ImageUrl and (with some teasing) Accessory
    • MvxSimpleTableViewSource.cs
      • inherits from MvxTableViewSource
      • provides a single cell type for all items in the collection - via string nibName in the ctor
      • within these cells you can bind what you like - see videos (later)
    • MvxActionBasedTableViewSource.cs - provides some Func<>style hooks to allow you to implement GetOrCreateCellFor without inheriting a new class from MvxTableViewSource

    Generally I use:

    • in demos:
      • a MvxStandardTableViewSource - because I get a list without having to create a custom cell
    • in real code:
      • a MvxSimpleTableViewSource when I only need one cell type
      • a custom class inheriting from MvxTableViewSource when I need multiple cell types - e.g. see below

    A general TableSource with multiple cell types typically looks like PolymorphicListItemTypesView.cs:

    public class PolymorphicListItemTypesView
        : MvxTableViewController
    {
        public PolymorphicListItemTypesView()
        {
            Title = "Poly List";
        }
    
        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
    
            var source = new TableSource(TableView);
            this.AddBindings(new Dictionary<object, string>
                {
                    {source, "ItemsSource Animals"}
                });
    
            TableView.Source = source;
            TableView.ReloadData();
        }
    
        public class TableSource : MvxTableViewSource
        {
            private static readonly NSString KittenCellIdentifier = new NSString("KittenCell");
            private static readonly NSString DogCellIdentifier = new NSString("DogCell");
    
            public TableSource(UITableView tableView)
                : base(tableView)
            {
                tableView.RegisterNibForCellReuse(UINib.FromName("KittenCell", NSBundle.MainBundle),
                                                  KittenCellIdentifier);
                tableView.RegisterNibForCellReuse(UINib.FromName("DogCell", NSBundle.MainBundle), DogCellIdentifier);
            }
    
            public override float GetHeightForRow(UITableView tableView, NSIndexPath indexPath)
            {
                return KittenCell.GetCellHeight();
            }
    
            protected override UITableViewCell GetOrCreateCellFor(UITableView tableView, NSIndexPath indexPath,
                                                                  object item)
            {
                NSString cellIdentifier;
                if (item is Kitten)
                {
                    cellIdentifier = KittenCellIdentifier;
                }
                else if (item is Dog)
                {
                    cellIdentifier = DogCellIdentifier;
                }
                else
                {
                    throw new ArgumentException("Unknown animal of type " + item.GetType().Name);
                }
    
                return (UITableViewCell) TableView.DequeueReusableCell(cellIdentifier, indexPath);
            }
        }
    }
    

    This video is very informative on how to create custom cells, but appears to be out-of-date

    It was made just pre-Xamarin 2.0 and pre-V3 but the principles are very similar.

    The code for that article has been updated - see https://github.com/slodge/MvvmCross-Tutorials/tree/master/MonoTouchCellTutorial

    Beyond that:

    • there's a lot of demos of table use in the N+1 series - indexed at http://mvvmcross.wordpress.com

      • N=2 and N=3 are very basic
      • N=6 and N=6.5 covers a book list (a good place to start)
      • N=11 covers collection views
      • N=12 to N=17 make a large app with a list/table from a database
    • the "Working with Collections" sample has quite a lot of Table and List code - https://github.com/slodge/MvvmCross-Tutorials/tree/master/Working%20With%20Collections

    • tables are used during the Evolve presentation - http://xamarin.com/evolve/2013#session-dnoeeoarfj

    • there are other samples available - see https://github.com/slodge/MvvmCross-Tutorials/ (or search on GitHub for mvvmcross - others are also posting samples)

    Also, I'm using a UITableView in a regular MvxViewController because I can't seem to get the MvxTableViewController to work with a xib, which this question seems to suggest isn't currently possible.

    I think that has since been fixed - see MvxTableViewController.cs#L33

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