Xamarin Forms: GetAsync not working in SearchBar event handler

Question

I am attempting to make a simple app that enables the user to search for movies using themoviedb api. If I hardcode my search query in the OnAppearing my method, GetAsync works perfectly. However, if I try and take the search term from the user in a SearchBar_TextChanged event handler, GetAsync hangs and never returns. I have searched a few day's for a solution, I assume it has something to do with me mismanaging my await and async calls, or, something to do with the TextChanged event blocking the request. Here is my code, thanks in advance for any solutions/suggestions.

public partial class MovieSearch : ContentPage
{
    private HttpClient _client = new HttpClient();
    private const string URL = "movie?api_key=9d9cb312367f0f2deaa383f9a8fd64d2&query=";//not the full link

    public MovieSearch()
    {

        InitializeComponent();
    }

    async void SearchBar_TextChanged(object sender, Xamarin.Forms.TextChangedEventArgs e)
    {
        if (e.NewTextValue == null)
            return;
        if (String.IsNullOrEmpty(e.NewTextValue))
            return;

        var response = await _client.GetAsync(URL + e.NewTextValue);
        var content = await response.Content.ReadAsStringAsync();
        var root = JsonConvert.DeserializeObject<RootObject>(content);
        movieListView.ItemsSource = root.results;
        movieListView.IsVisible = root.results.Any();
        label.IsVisible = !movieListView.IsVisible;
    }
}

I would add some logic to prevent it from making a new request when the prior request is still in progress — Jason, Aug 31 '18 at 17:08
set a bool when searching, and don't start a new search when it is already set — Jason, Sep 01 '18 at 01:26
@Jason I feel like something about the event handler is blocking my GetAsync call — Cian Mc Sweeney, Sep 01 '18 at 23:02
I think that's unlikely. You might try creating a new HttpClient each time instead of reusing it — Jason, Sep 02 '18 at 00:22
@Jason unfortunately that's not working either, app doesn't hang anymore, but doesn't return any data either — Cian Mc Sweeney, Sep 02 '18 at 20:35

score 0 · Answer 1 · answered Aug 12 '21 at 15:02

0

you need to use TaskCancellationToken and cancel the request before asking for another one.

answered Aug 12 '21 at 15:02

Kubaizi

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Xamarin Forms: GetAsync not working in SearchBar event handler

1 Answers1