I have a developing application with a serious problem in passing data from one screen to another. When I started, I made a start screen with a listview, in it I had a searchbox where the user typed a brief description of a vehicle and clicking on the search button, the system returned the data, triggering the icommand, causing a viewmodel to process data and by the observablecollection displayed in the listview. Now I had to implement an advanced search screen, I have not put any code to filter it, I just put the fetch button that executes the same icommand, I make a debug, the variable that receives the list of data is populated, however the listview continues without anything.
I'm almost desperate because of this, my knowledge of C # is minimal, and I'm new to Visual Studio, to make matters worse.
If someone can help me, thank you.
Follow the first screen
namespace TvCar.Views
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class PesquisaDetalhada : ContentPage, INotifyPropertyChanged
{
public PesquisaDetalhada()
{
InitializeComponent();
this.BindingContext = new ViewModels.Veiculo_ViewModel();
string img_condicao, img_marca, img_modelo, img_ano, img_versao, img_preco, img_km, img_cambio, img_combustivel, img_portas, img_cor, img_cidade;
switch (Device.RuntimePlatform)
{
case Device.iOS:
img_condicao = "img_condicao.png";
img_marca = "img_marca.png";
img_modelo = "img_modelo.png";
img_ano = "img_ano.png";
img_versao = "img_versao.png";
img_preco = "img_preco.png";
img_km = "img_km.png";
img_cambio = "img_cambio.png";
img_combustivel = "img_combustivel.png";
img_portas = "img_portas.png";
img_cor = "img_cor.png";
img_cidade = "img_cidade.png";
break;
case Device.Android:
default:
img_condicao = "img_condicao.png";
img_marca = "img_marca.png";
img_modelo = "img_modelo.png";
img_ano = "img_ano.png";
img_versao = "img_versao.png";
img_preco = "img_preco.png";
img_km = "img_km.png";
img_cambio = "img_cambio.png";
img_combustivel = "img_combustivel.png";
img_portas = "img_portas.png";
img_cor = "img_cor.png";
img_cidade = "img_cidade.png";
break;
}
listView.ItemsSource = new List<Item>
{
new Item {Name = "Condição",Image = img_condicao} ,
new Item {Name = "Marca",Image = img_marca} ,
new Item {Name = "Modelo",Image = img_modelo},
new Item {Name = "Ano",Image = img_ano},
new Item {Name = "Versão",Image = img_versao},
new Item {Name = "Preço",Image = img_preco},
new Item {Name = "KM",Image = img_km},
new Item {Name = "Cambio",Image = img_cambio},
new Item {Name = "Combustível",Image = img_combustivel},
new Item {Name = "Portas",Image = img_portas},
new Item {Name = "Cor",Image = img_cor},
new Item {Name = "Cidade",Image = img_cidade}
};
}
private async void Button_Clicked(object sender, EventArgs e)
{
await App.Current.MainPage.Navigation.PushAsync(new Views.ListarAnuncios());
}
class Item
{
public string Name { get; set; }
public string Image { get; set; }
}
}
Follow the second screen (Listview)
namespace TvCar.Views
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class ListarAnuncios : INotifyPropertyChanged
{
public ListarAnuncios()
{
InitializeComponent();
this.Detalhes.ItemsSource = null;
this.Detalhes.ItemsSource = new ObservableCollection<ViewModels.Veiculo_ViewModel>();
this.Detalhes.ItemTapped += async (sender, e) =>
{
var detalhe = e.Item as Model.Veiculo_Cadastro;
await App.Current.MainPage.Navigation.PushAsync(new Views.VeiculoDetalhes(detalhe));
MainPage.mcodveiculo = detalhe.VEICULO_CODIGO;
MainPage.mDesVeiculo = detalhe.VEICULO_DESCRICAO;
MainPage.Atualiza_Visitas(sender: PropertyChanged);
};
}
internal static ListView Listarlv;
//private void OnTextChanged()
//{
// MainPage.DadosBusca = string.Concat("AND UPPER(A.VEICULO_VERSAO) LIKE UPPER('%", Pesquisar.Text, "%') ");
//}
public class StringCaseConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
string param = System.Convert.ToString(parameter) ?? "u";
switch (param.ToUpper())
{
case "U":
return ((string)value).ToUpper();
case "L":
return ((string)value).ToLower();
default:
return ((string)value);
}
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotSupportedException();
}
}
public event PropertyChangedEventHandler PropertyChanged;
public VeiculoDetalhes Selecao_Item { get; set; }
}
Follow the class that searches the data
namespace TvCar.ViewModels
{
public sealed class Veiculo_ViewModel : INotifyPropertyChanged // classe
{
public ICommand CarregarCommand { get; set; }
public VeiculoDetalhes Selecao_Item { get; set; }
private ObservableCollection<Model.Veiculo_Cadastro> Anuncio;
public ObservableCollection<Model.Veiculo_Cadastro> Anuncios
{
get { return Anuncio; }
set
{
Anuncio = value;
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Anuncios)));
}
}
public Veiculo_ViewModel()
{
CarregarCommand = new Xamarin.Forms.Command(async () =>
{
var Anuncio = await ApiAnuncios.Api_Rest.GetAsync();
Anuncios = new ObservableCollection<Model.Veiculo_Cadastro>(Anuncio);
TvCar.MainPage.MinhaLista = new ListView();
TvCar.MainPage.MinhaLista.ItemsSource = null;
TvCar.MainPage.MinhaLista.ItemsSource = Anuncios;
});
}
public event PropertyChangedEventHandler PropertyChanged;
}