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how can I bind a full response from SQLite?

I am making a ListView inside my C# file. But instead of that I want to add the data I get from sqlite too the xaml file with data binding so I can still edit the layout with xaml. So every response from sqlite needs to be added as label(<TextCell Text="{Binding Name}" />).

My question: How can I bind the response from GetCategoryByMenuID to TextCell Text="{Binding Name}"?

xaml page (CategoriePage.xaml):

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="AmsterdamTheMapV3.CategoriePage">
  <ListView x:Name="listView">
    <ListView.ItemTemplate>
      <DataTemplate>
        <TextCell Text="{Binding Name}" />
      </DataTemplate>
    </ListView.ItemTemplate>
  </ListView>
</ContentPage>

Back-end / C# (CategoriePage.xaml.cs) :

namespace AmsterdamTheMapV3
{
    public partial class CategoriePage : ContentPage
    {

        public CategoriePage(String txt)
        {
            InitializeComponent();
            var layout = new StackLayout { Padding = new Thickness(5, 10) };
            int page = Int32.Parse(txt);
            this.Content = layout;

            var categories = App.Database.GetCategoryByMenuID(page);

            var datatemplate = new DataTemplate(() =>
            {
                var nameLabel = new Label();
                nameLabel.SetBinding(Label.TextProperty, "Name");
                //nameLabel.SetBinding(Label.idProperty, "Name");

                return new ViewCell { View = nameLabel };
            });

            var listView = new ListView
            {
                ItemsSource = categories,
                ItemTemplate = datatemplate
            };

            layout.Children.Add(listView);
        }
    }
}

GetCategoryPage function:

public List<Categories> GetCategoryByMenuID(int menuID)
{
    lock (locker)
    {
        return db.Table<Categories>().Where(x => x.Menu_ID == menuID).ToList();
    }
}
like image 960
N. Smeding Avatar asked Nov 24 '16 10:11

N. Smeding


2 Answers

Given

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="AmsterdamTheMapV3.CategoriePage">
  <ListView x:Name="listView">
    <ListView.ItemTemplate>
      <DataTemplate>
        <ViewCell>
          <ViewCell.View>
            <StackLayout>
              <Label Text="{Binding Name}" />
            </StackLayout>
          </ViewCell.View>
        </ViewCell>
      </DataTemplate>
    </ListView.ItemTemplate>
  </ListView>
</ContentPage>

Update code behind

namespace AmsterdamTheMapV3 {
    public partial class CategoriePage : ContentPage {

        public CategoriePage(string txt) {
            InitializeComponent();
            this.Appearing += (s,e) => {
                if(NotInDesignMode) {
                    int page = 0;
                    if(int.TryParse(txt, out page)){
                        var categories = App.Database.GetCategoryByMenuID(page);
                        this.listView.ItemsSource = categories;
                    }
                }
            };
        }

        bool NotInDesignMode {
            get { return Application.Current != null; }
        }
    }
}
like image 158
Nkosi Avatar answered Nov 08 '22 06:11

Nkosi


You could do it the ugly and fast-to-implement way (in your GetCategoryByMenuID method, Run an update name by id, which will run on categories).

Or by making a collection that'd be menuID based instead of index based as a regular list.

 public class CategoriesCollection<T> : KeyedCollection<int, T>
    {
        protected override int GetKeyForItem(T item)
        {
            return (item as Category).Id;
        }

        /// <summary>
        /// Method to get the index into the List{} in the base collection for an item that may or may 
        /// not be in the collection. Returns -1 if not found.
        /// </summary>
        protected override int GetItemIndex(T itemToFind)
        {
            int keyToFind = GetKeyForItem(itemToFind);
            return BaseList.FindIndex((T existingItem) =>
                                      GetKeyForItem(existingItem).Equals(keyToFind));
        }
    }

sql should be OK storing/retrieving anything that's icollection, so while you couldn't use a dictionary, this should work. At least it has worked for me in sqlite (before I've moved away from sqliteAPI to entityframework)

like image 1
Oyiwai Avatar answered Nov 08 '22 07:11

Oyiwai