Extensible Listview avec Xamarin et Prism

Question

Je suis Tring pour créer un listview extensible et je suis cet exemple:

Example

Le problème est que j'utilise Prism comme cadre MVVM, je ne peut pas utiliser un événement, j'utilise une commande. Voici le code:

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" 
     xmlns:prism="clr-namespace:Prism.Mvvm;assembly=Prism.Forms" 
     prism:ViewModelLocator.AutowireViewModel="True" 
     x:Class="JDeliveryCP.Views.DocumentsPage" 
     x:Name="TheDocumentsPage"> 
<ContentPage.Content> 
    <ListView x:Name="lstDocuments" GroupDisplayBinding="{Binding Title}" RowHeight="75" IsGroupingEnabled="True" ItemsSource="{Binding ExpandedDocuments}" > 
     <ListView.GroupHeaderTemplate> 
      <DataTemplate> 
       <ViewCell> 
        <StackLayout Orientation="Horizontal" > 
         <ContentView> 

          <Grid x:Name="cell"> 
           <Grid.ColumnDefinitions> 
            <ColumnDefinition Width="1*" /> 
           </Grid.ColumnDefinitions> 
           <Label Text="{Binding Title}"/> 

           <ContentView.GestureRecognizers> 
            <TapGestureRecognizer Command="{Binding HeaderTappedCommand}" BindingContext="{Binding Source={x:Reference lstDocuments}, Path=BindingContext}" 
                CommandParameter="{Binding Source={x:Reference cell}, Path=BindingContext}" /> 
           </ContentView.GestureRecognizers> 
          </Grid> 
         </ContentView> 
        </StackLayout> 
       </ViewCell> 
      </DataTemplate> 
     </ListView.GroupHeaderTemplate> 
     <ListView.ItemTemplate> 
      <DataTemplate> 
       <ImageCell Text="{Binding Description}" ImageSource="icon.png" Height="75" /> 
      </DataTemplate> 
     </ListView.ItemTemplate> 
    </ListView> 
</ContentPage.Content> 

PageViewModel:

using JDeliveryCP.FEModels; 
using Prism.Commands; 
using Prism.Mvvm; 
using System; 
using System.Collections.Generic; 
using System.Collections.ObjectModel; 
using System.ComponentModel; 
using System.Linq; 
using System.Windows.Input; 
using Xamarin.Forms; 

namespace JDeliveryCP.ViewModels 
{ 
    public class DocumentsPageViewModel : BindableBase, INotifyPropertyChanged 
    { 
     private ObservableCollection<DocumentGroupModel> _documents; 
     private ObservableCollection<DocumentGroupModel> _expandedDocuments; 
     private ICommand headerTappedCommand; 
    public ICommand HeaderTappedCommand 
    { 
     get { return headerTappedCommand; } 
    } 

    public ObservableCollection<DocumentGroupModel> Documents 
    { 
     get { return _documents; } 
     set { SetProperty(ref _documents, value); } 
    } 

    public ObservableCollection<DocumentGroupModel> ExpandedDocuments 
    { 
     get { return _expandedDocuments; } 
     set { SetProperty(ref _expandedDocuments, value); } 
    } 

    public DocumentsPageViewModel() 
    { 

     headerTappedCommand = new Command(HeaderTapped); 
     //TEST -START- 
     _documents = new ObservableCollection<DocumentGroupModel> 
     { 
      new DocumentGroupModel(897, "Cliente 1", false) 
      { 
        new DocumentModel { Description = "documento 1"}, 
        new DocumentModel { Description = "documento 2"}, 
        new DocumentModel { Description = "documento 3"} 
      }, 
      new DocumentGroupModel(543, "Cliente 2", false) 
      { 
        new DocumentModel { Description = "documento 4"}, 
        new DocumentModel { Description = "documento 5"} 
      } 
     }; 
     //TEST -END- 

     UpdateListContent(); 
    } 

    async void HeaderTapped(object sender, EventArgs args) 
    { 
     HeaderTapped(sender); 
    } 

     private void HeaderTapped(object sender) 
    { 
     DocumentGroupModel selected = ((DocumentGroupModel)(sender)); 
     DocumentGroupModel found = _documents.FirstOrDefault(x => x.Id == selected.Id); 
     found.Expanded = !found.Expanded;  
     UpdateListContent(); 
     OnPropertyChanged(new PropertyChangedEventArgs("Expanded")); 
    } 


    private void UpdateListContent() 
    { 

     _expandedDocuments = new ObservableCollection<DocumentGroupModel>(); 
     foreach(DocumentGroupModel group in _documents) 
     { 
      DocumentGroupModel newGroup = new DocumentGroupModel(group.Id, group.Title, group.Expanded); 

      if (group.Expanded) 
      { 
       foreach(DocumentModel doc in group) 
       {       
        newGroup.Add(doc); 
       } 
      } 
      _expandedDocuments.Add(newGroup); 
     }    

    } 

} 

}

GROUPE Modèle:

using System; 
using System.Collections.Generic; 
using System.Collections.ObjectModel; 
using System.ComponentModel; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 

namespace JDeliveryCP.FEModels 
{ 
    public class DocumentGroupModel : ObservableCollection<DocumentModel>, INotifyPropertyChanged 
    { 
     private bool _expanded; 

     public string Title { get; set; } 

     public int Id { get; set; } 

     public bool Expanded 
     { 
      get { return _expanded; } 
      set 
      { 
       if (_expanded != value) 
       { 
        _expanded = value;     
        OnPropertyChanged(new PropertyChangedEventArgs("Expanded"));     
       } 
      } 
     } 

     public DocumentGroupModel(int id, string title, bool expanded = true) 
     { 
      Id = id; 
      Title = title; 
      Expanded = expanded; 
     } 
    } 
} 

ARTICLE Modèle:

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 

namespace JDeliveryCP.FEModels 
{ 
    public class DocumentModel 
    { 
     public string Description { get; set; } 


    } 
} 

Le Listview est rendu correctement et les travaux commande du robinet, mais il ne montre pas les lignes du groupe exploité, la mise en page doesn ne change pas. J'ai essayé de déboguer la méthode "HeaderTapped" et les groupes sont correctement peuplés. Je ne sais pas si cela peut être un problème d'actualisation du widget ou des problèmes de liaison entre le modèle de ligne et le pageviewmodel.

Merci pour votre aide!

Answer 1

J'ai résolu le problème moi-même.

Je changé ceci:

private void HeaderTapped(object sender) 
    { 
     DocumentGroupModel selected = ((DocumentGroupModel)(sender)); 
     DocumentGroupModel found = _documents.FirstOrDefault(x => x.Id == selected.Id); 
     found.Expanded = !found.Expanded;  
     UpdateListContent(); 
     OnPropertyChanged(new PropertyChangedEventArgs("Expanded")); 
    } 

avec ceci:

 private void HeaderTapped(object sender) 
     { 
      DocumentGroupModel selected = ((DocumentGroupModel)(sender)); 
      DocumentGroupModel found = _documents.FirstOrDefault(x => x.Id == selected.Id); 
      found.Expanded = !found.Expanded;  
      UpdateListContent(); 
      OnPropertyChanged(new PropertyChangedEventArgs("ExpandedDocuments")); 
     } 

Je changé que l'argument "OnPropertyChanged".