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using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms.CustomAttributes;
using Xamarin.Forms.Internals;
namespace Xamarin.Forms.Controls.TestCasesPages
{
[Preserve (AllMembers=true)]
[Issue (IssueTracker.Github, 1851, "ObservableCollection in ListView gets Index out of range when removing item", PlatformAffected.Android)]
public class Issue1851 : ContentPage
{
public Issue1851 ()
{
var grouping = new Grouping<string, string>("number", new List<string> { "1", "2", "3", "4", "5", "6", "7", "8", "9" });
var groupings = new ObservableCollection<Grouping<string, string>>
{
new Grouping<string, string>("letters", new List<string> {"a", "b", "c", "d", "e", "f", "g", "h", "i"}),
new Grouping<string, string>("colours", new List<string> {"red", "green", "blue", "white", "orange", "purple", "grey", "mauve", "pink"}),
grouping,
};
var listview = new ListView
{
HasUnevenRows = true,
IsGroupingEnabled = true,
ItemsSource = groupings,
ItemTemplate = new DataTemplate(typeof(CellTemplate)),
GroupDisplayBinding = new Binding("Key")
};
var groupbtn = new Button() { Text = "add/remove group" };
bool group = true;
groupbtn.Clicked += (sender, args) =>
{
listview.GroupShortNameBinding = new Binding ("Key");
if (group)
{
group = false;
// ***** Crashes here
groupings.Remove(grouping);
}
else
{
group = true;
groupings.Add(grouping);
}
};
Content = new StackLayout
{
Children =
{
groupbtn,
listview,
}
};
}
}
public class CellTemplate : ViewCell
{
protected override void OnBindingContextChanged()
{
base.OnBindingContextChanged();
var text = BindingContext as string;
if (text == null)
return;
View = new Label { Text = text };
}
}
public class Grouping<TKey, TElement> : ObservableCollection<TElement>
{
public Grouping(TKey key, IEnumerable<TElement> items)
{
Key = key;
foreach (var item in items)
Items.Add(item);
}
public TKey Key { get; private set; }
}
}
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