Retrieve firebase data from binding ListView Xamarin Forms

Question

I have a listview where I retrieve data from firebase with an helper and show it by binding them in .xaml, like that:

the helper:

public class FirebaseHelper
public async Task<List<Books>> GetAllBooks()
        {
            return (await firebase
              .Child("Books")
              .OnceAsync<Books>()).Select(item => new Books
              {
                  Title = item.Object.Title,
                  Author = item.Object.Author,
                  Genre = item.Object.Genre,
                  Cover  = item.Object.Cover
              }).ToList();
        }

the page.xaml.cs

public List<Books> libriall;

protected async override void OnAppearing()
        { 
            base.OnAppearing();
            bookall = await firebaseHelper.GetAllBooks();
            listbook.ItemsSource = bookall;
        }

and a part of the listview listbook in the .xaml file:

<Label 
       TextColor="#33272a"
       Text="{Binding Title}"
       x:Name="bTitle"/>

Ok now I put a Button in the ViewCell and I want to get the book title and use it in a PostAsync, so I basically need to get the single title book and put it in a string.

Already created a method like that in the helper:


public async Task<string> getTitle()
        {
            return (await firebase
              .Child("Books")
              .OnceAsync<Books>()).Select(item => new Books
              {
                  Title = item.Title
              }).ToString();
        }

But I don't know how to link books properties to the single viewcell they are displayed with the binding, any idea?

if GetAllBooks retrieves the title, why do you need another method getTitle to also get the title? — Jason
getAllBooks returns a List, GetTitle returns a string instead — Fio
Yes, but the list contains a list of Book, and each Book already has a Title property. Why do you need to retrieve it again, instead of just pulling it from the Book that you already have? You are clicking a row in your list, you just want to get the title of the book for that row? — Jason
I only want the title from the row I'm interacting with, if I use GetAllBooks I get the list of all the books with their properties while I only want a string. — Fio
you do not need to call GetAllBooks again, you already have all of that data in the ItemsSource — Jason

Jason Jason · Accepted Answer · 2020-11-07T23:06:23

you do not need to get the data from your service again, you already have it in the ItemsSource for your list

void ButtonClicked(object sender, EventArgs args)
{
  Button btn = (Button)sender;

  // the BindingContext of the Button will be the Books
  // object for the row you clicked on 
  var book = (Books)btn.BindingContext;

  // now you can access all of the properties of Books
  var title = book.Title;
}

Retrieve firebase data from binding ListView Xamarin Forms

1 Answers