Xamarin Forms CollectionView is empty - xamarin

Question

I have a Xamarin Forms CollectionView, contained within a RefreshView. The binding source is populated but its not showing anything in the CollectionView. I know the binding source is populated as I show a count in the toolbar. Can anyone spot why the list is empty?
Here is my Content Page with my RefreshView and CollectionView:
<ContentPage.ToolbarItems>
<ToolbarItem Text="Add" Command="{Binding AddDogCommand}" />
<ToolbarItem Text="{Binding Dogs.Count}"></ToolbarItem>
</ContentPage.ToolbarItems>
<RefreshView x:DataType="local:MyDogsViewModel" Command="{Binding LoadDogsCommand}" IsRefreshing="{Binding IsBusy, Mode=TwoWay}">
<CollectionView ItemsLayout="HorizontalList" ItemsSource="{Binding Dogs}">
<CollectionView.ItemTemplate>
<DataTemplate>
<Grid WidthRequest="100">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Label Grid.Column="1"
Text="{Binding DogName}"
FontAttributes="Bold" TextColor="Red"/>
<Label Grid.Row="1"
Grid.Column="1"
Text="{Binding Nickname}"
FontAttributes="Italic" TextColor="Green"
VerticalOptions="End" />
</Grid>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</RefreshView>
Here is my ViewModel
public class MyDogsViewModel : BaseViewModel
{
private DogModel _selectedItem;
private DogService dogService = new DogService();
private string _dogName;
private string _nickname;
public ObservableCollection<DogModel> Dogs { get; }
public Command LoadDogsCommand { get; }
public Command<DogModel> ItemTapped { get; }
public Command AddDogCommand { get; }
public Command SaveDogCommand { get; }
public string DogName
{
get => _dogName;
set => SetProperty(ref _dogName, value);
}
public string Nickname
{
get => _nickname;
set => SetProperty(ref _nickname, value);
}
public MyDogsViewModel()
{
Title = "My Dogs";
Dogs = new ObservableCollection<DogModel>();
LoadDogsCommand = new Command(async () => await ExecuteLoadDogsCommand());
ItemTapped = new Command<DogModel>(OnItemSelected);
AddDogCommand = new Command(OnAddDog);
SaveDogCommand = new Command(OnSaveDog);
}
async Task ExecuteLoadDogsCommand()
{
IsBusy = true;
try
{
Dogs.Clear();
var dogs = await dogService.GetDogsAsync();
foreach (var d in dogs)
{
Dogs.Add(d);
}
}
catch (Exception ex)
{
Debug.WriteLine("Exception: " + ex);
}
finally
{
IsBusy = false;
}
}
public void OnAppearing()
{
IsBusy = true;
}
private async void OnAddDog(object obj)
{
await Shell.Current.GoToAsync(nameof(AddDogPage));
}
private async void OnSaveDog(object obj)
{
AddDogModel model = new AddDogModel
{
DogName = DogName,
Nickname = Nickname
};
await dogService.AddDog(model);
await Shell.Current.GoToAsync("..");
}
async void OnItemSelected(DogModel dog)
{
if (dog == null)
return;
}
}
DogModel class
public class DogModel
{
public int Id { get; set; }
public string DogName { get; set; }
public string Nickname { get; set; }
}

Answer 1

keep your xaml the same and i will edit your ViewModel and take out the properties that is causing you the issue ;
public class MyDogsViewModel : BaseViewModel
{
private DogModel _selectedItem;
private DogService dogService = new DogService();
private string _dogName;
private string _nickname;
private ObservableCollection<DogModel> dogs;
public ObservableCollection<DogModel> Dogs
{
get{return dogs;}
set{dogs=value;}
}
public Command LoadDogsCommand { get; set; }
public Command<DogModel> ItemTapped { get; set;}
public Command AddDogCommand { get; set;}
public Command SaveDogCommand { get; set;}
public MyDogsViewModel()
{
Title = "My Dogs";
Dogs = new ObservableCollection<DogModel>();
LoadDogsCommand = new Command(async () => await ExecuteLoadDogsCommand());
ItemTapped = new Command<DogModel>(OnItemSelected);
AddDogCommand = new Command(OnAddDog);
SaveDogCommand = new Command<object>(OnSaveDog);
}
async Task ExecuteLoadDogsCommand()
{
IsBusy = true;
try
{
Dogs.Clear();
var dogs = await dogService.GetDogsAsync();
foreach (var d in dogs)
{
Dogs.Add(d);
}
}
catch (Exception ex)
{
Debug.WriteLine("Exception: " + ex);
}
finally
{
IsBusy = false;
}
}
public void OnAppearing()
{
IsBusy = true;
}
private async void OnAddDog(object obj)
{
await Shell.Current.GoToAsync(nameof(AddDogPage));
}
private async void OnSaveDog(object obj)
{
DogModel newdog = obj as DogModel;
await dogService.AddDog(newdog);
await Shell.Current.GoToAsync("..");
}
async void OnItemSelected(DogModel dog)
{
if (dog == null)
return;
}
}
dont forget to bind to the viewmodel. in the xaml.cs add this in the constuctor.
this.BindingContext = new MyDogsViewModel();