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GordonS-9701 avatar image
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GordonS-9701 asked JessieZhang-2116 edited

Xamarin Forms CarouselView trying to Bind Loop property

I have a CarouselView with Loop enabled, which works fine for 2 or more items. However, it doesn't work well when there is only 1. It's weird that you can scroll and keep getting the same item!

Anyway, I have added code to check the number of items and set Loop to True if items > 1, otherwise it is set to false.

However, even though the code runs to set the value of Loop, the CarouselView itself does not change.

I am using a ViewModel which has a "Base" model containing a "SetProperty" method where "OnPropertyChanged" is called.

Should I be able to dynamically change the Loop setting, or is it set once only?

dotnet-xamarin
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1 Answer

JessieZhang-2116 avatar image
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JessieZhang-2116 answered JessieZhang-2116 edited

Hello,


Welcome to our Microsoft Q&A platform!


Update 2

Yes, it is just the case as you said. If we set an initial value for property Loop in CarouselView, once we change the value for the binded value, the UI couldn't update accordingly.

  <CarouselView ItemsSource="{Binding items}" Loop="{Binding EnableCarouselLoop}" >

And this is a known issue , you can follow it up here:https://github.com/xamarin/Xamarin.Forms/issues/13706 .


Update 1

Should I be able to dynamically change the Loop setting, or is it set once only?

I have a CarouselView with Loop enabled, which works fine for 2 or more items. However, it doesn't work well when there is only 1. It's weird that you can scroll and keep getting the same item!

Anyway, I have added code to check the number of items and set Loop to True if items > 1, otherwise it is set to false.

However, even though the code runs to set the value of Loop, the CarouselView itself does not change.


I couldn't fully understand what you mean. Does the Loop in the item of the CarouselView ?And under what circumstances do you want to change this value?

Of course, you can change the Loop setting after you init a value for it first.
Take the Xamarin.Forms - CarouselView for example, we can add the variable (`Loop`)in the item model, just as the Monkey.cs do(e.g. IsFavorite ) :

 public class Monkey
 {
     public string Name { get; set; }
     public string Location { get; set; }
     public string Details { get; set; }
     public string ImageUrl { get; set; }
     public bool IsFavorite { get; set; }
     // add variable Loop here
     public bool Loop { get; set; } 
 }

And in page HorizontalSwipeItemsPage.xaml ,we can trigger command FavoriteCommand in viewmode MonkeysViewModel.cs

          <SwipeView.TopItems>
                            <SwipeItems>
                                   <SwipeItem Text="Favorite"
                                            IconImageSource="favorite.png"
                                            BackgroundColor="LightGreen"
                                            Command="{Binding Source={x:Reference carouselView}, Path=BindingContext.FavoriteCommand}"
                                           CommandParameter="{Binding}" />
                          </SwipeItems>
         </SwipeView.TopItems>

The FavoriteCommand is:

    public ICommand FavoriteCommand => new Command<Monkey>(FavoriteMonkey);
     void FavoriteMonkey(Monkey monkey)
     {
         monkey.IsFavorite = !monkey.IsFavorite;
     }

Here, we can change the value of IsFavorite . So, you can do the same thing for the variable Loop .


Best Regards,


Jessie Zhang


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In the XAML, I have this on the CarouselView:

 Loop="{Binding EnableCarouselLoop}"

In ViewModel, I have:

     public bool EnableCarouselLoop
     {
         get => _enableCarouselLoop;
         set => SetProperty(ref _enableCarouselLoop, value);
     }

In the "Get Data" code in the ViewModel, I have:

 EnableCarouselLoop = Items.Count > 1;


So, I am expecting that if there are 2 or more items then Loop will be enabled (True), otherwise it will be Disabled (False). If it is enabled, I expect to be able to scroll both ways ... but I can't, when there are 2 or more items in the Carousel. So, either my code isn't working or the Loop value cannot be changed once the CarouselView is setup.

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I have updated the answer, you can check my answer.

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I haven't tried your code yet, but how does it update EnableCarouselLoop after you add a second item using the Button?

0 Votes 0 ·

Sorry, I misunderstood what you meant. I have updated my answer. You can check up the updated part.

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