CODEWITHSUNDEEP
c#xamarinxamarin.formsxamarin.forms.collectionview
KevinUK
KevinUK

Reputation: 5153

CollectionView updating ImageButton scroll repeating UI issue

I've got a CollectionView containing an ImageButton. When the image is pressed I replace a.png with b.png.

This is working fine but when I scroll down the list, every 10th item is now showing b.png!

If instead of setting the button.source, I called the line below again after saving to the DB which solves my problem but then I start at the top of the list and not at the current position I was at:

ItemsListView.ItemsSource = items;

How can I set the button.source without it creating this bug on every 10th item?

    <CollectionView x:Name="Items">
                <CollectionView.ItemTemplate>
                        <DataTemplate>
                           <ImageButton CommandParameter="{Binding Id}" Source="a.png" Clicked="OnInventoryClicked" />
                        </DataTemplate>
                    </CollectionView.ItemTemplate>
    </CollectionView>

    void OnInventoryClicked(object sender, EventArgs e)
            {
                    var button = (sender as ImageButton);
                    var itemId = button.CommandParameter.ToString();
                    var inventoryItem = await App.Database.GetItemAsync(itemId);
                    inventoryItem.IsInInventory = !inventoryItem.IsInInventory;
                    await App.Database.SaveItemAsync(inventoryItem);
                    button.Source = inventoryItem.IsInInventory? "b.png" : "a.png";         
            }

Upvotes: 1

Views: 221

Answers (1)

Wendy Zang - MSFT
Wendy Zang - MSFT

Reputation: 10978

You could change with the souce property.

Xaml:

<CollectionView x:Name="Items" ItemsSource="{Binding infos}">
    <CollectionView.ItemTemplate>
        <DataTemplate>
            <!--<ImageButton
                Clicked="OnInventoryClicked"
                CommandParameter="{Binding Id}"
                Source="a.png" />-->
            <ImageButton Clicked="ImageButton_Clicked" Source="{Binding image}" />
        </DataTemplate>
    </CollectionView.ItemTemplate>
</CollectionView>

Code behind:

public partial class MainPage : ContentPage
{

    public ObservableCollection<Info> infos { get; set; }
    public MainPage()
    {
        InitializeComponent();
        infos = new ObservableCollection<Info>()
        {
            new Info{image = "pink.jpg"        },
            new Info{image = "pink.jpg"        },
            new Info{image = "pink.jpg"        },
            new Info{image = "pink.jpg"        },
            new Info{image = "pink.jpg"        },

        };


        this.BindingContext = this;
    }

    private void ImageButton_Clicked(object sender, EventArgs e)
    {
        var button = (sender as ImageButton);
        button.Source = "dog.jpg";
    }


}
public class Info
{
    public string image { get; set; }
}

Upvotes: 2

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