SearchBar in Listview JSON

tecomunico · August 2017

Hi, Guys. Someone can explain me how search value in Listview ?
My XAML is:

My Code Behind is:

My Device is:

Thanks,

kizanlik · August 2017

hi @tecomunico

Yes. AllDevice is null because you do not set it. It is just initialized at the beginning.

I see two options. Modify your code and:

1) Use AllDevice instead of allDevice while deserializing recevied data.
2) Define allDevice in class not in LoadAll method and change this line:

AllListView.ItemsSource = AllDevice.Where(x => x.UnidadNumero.Contains(searchText)); // <- Upper case A, AllDevice

to

AllListView.ItemsSource = allDevice.Where(x => x.UnidadNumero.Contains(searchText)); // <- Lower case a, allDevice

tecomunico · August 2017

If I use a Static List, work fine, but when i use:

var allDevice = JsonConvert.DeserializeObject<List>(result);
AllListView.ItemsSource = allDevice;

Don't work.

tecomunico · August 2017

Thanks @kizanlik you are a GURU.
Work Fine !!!!!!

kizanlik · August 2017

Glad to hear that it works @tecomunico . Thank you but I am not a guru.

I think that your next question will be "Why ListView doesn't update when data is changed in the current collection?". At that point, before asking a question you need to understand INotifyPropertyChanged interface and ObservableCollection< T > class because List< T > doesn't trigger PropertyChangedEventHandler.

This is a completely new story. Don't waste your time. Don't pull your hair.

kizanlik · August 2017

Hi @tecomunico

Use Linq. Linq examples.

For your code:

using System.Linq; // <- must be added before namesapce definition
...    
AllListView.ItemsSource = AllDevice.where(device => device.IDCustomer.Contains("SearchBox text goes here"));
...

I didn't test the piece of code. Linq is the point here.

tecomunico · August 2017

Thanks @kizanlik, but not work.

My Code is:
using System.Net.Http;
using Xamarin.Forms;
using System.MPG.Models;
using System.Collections.Generic;
using System.MPG.Cells;
using Newtonsoft.Json;
using System.Linq;

namespace System.MPG
{
public partial class VerBusquedaPage : ContentPage
{
public List AllDevice = new List();

    public VerBusquedaPage()
    {
        InitializeComponent();
        AllListView.ItemTemplate = new DataTemplate(typeof(AllCells));
        LoadAll();
    }

    private void TextoCambiado(object sender, TextChangedEventArgs e)
    {
        string searchText = BarraSearchAll.Text;
        if (string.IsNullOrWhiteSpace(e.NewTextValue))
        {
            AllListView.ItemsSource = AllDevice;
        }else{
            AllListView.ItemsSource = AllDevice.Where(x => x.UnidadNumero.Contains(searchText));
        }
    }

    private async void LoadAll()
    {
        waitActivityIndicator.IsRunning = true;
        string result = string.Empty;
        try
        {
            HttpClient Cliente = new HttpClient();
            Cliente.BaseAddress = new Uri("http://www.mpg.work");
            string url = string.Format("/json/xamarin/json_buscarall.php");
            var response = await Cliente.GetAsync(url);
            result = response.Content.ReadAsStringAsync().Result;
        }
        catch (Exception ex)
        {
            await DisplayAlert("Error", string.Format("Your Smartphone Should Be Connected to Internet", ex.Message), "Ok");
            waitActivityIndicator.IsRunning = false;
            return;
        }
        waitActivityIndicator.IsRunning = false;
        var allDevice = JsonConvert.DeserializeObject<List<DeviceAll>>(result);
        AllListView.ItemsSource = allDevice;
    }
}

}

Picture:

Example:

Listview Working: The Listview show 3 Json Fields, yellow field is a Unit Number (UnidadNumero)

Not Show anything:

kizanlik · August 2017