Question

这是我的代码：

 public partial class MyGS: ContentPage {
   private GestioneSchedeViewModel _viewModel;

   public MyGS() {
     InitializeComponent();
     BindingContext = _viewModel  = new MyGSViewModel();
   }

  private void modifySch(object sender, EventArgs e)
   {
     SchedeItem item = (SchedeItem)((Image)sender).BindingContext;
     if (item == null) { return; }
     _viewModel.modifyItem(item.realm_id, item.list_id);
   }
  }

  public class MyGSViewModel: INotifyCollectionChanged {
   public event NotifyCollectionChangedEventHandler CollectionChanged;

   public ObservableCollection < SchItem > Items {get;private set;}

   public MyGSViewModel() {
    Items = new ObservableCollection<SchItem>();
    //Item Population 
   }

   public void modificaItem(int rid, int lid)
    {
      SchedeItem myItem = Items[lid];
      myItem.name = "New Text";
    }

   protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

   }

   public class SchItem : INotifyPropertyChanged {
     public int realm_id {get;set;}
     public int list_id {get;set;}
     public int name {get;set;}

     public event PropertyChangedEventHandler PropertyChanged;

     protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
   }

}

如何在图片点击时更改listview中带有名称的标签文字？目前，点击不会改变，并且列表视图中的目标项目中不显示“新文本”。

注意：XAML here

注意：在Android设备中进行调试

Answer 1

您必须在setter中为每个属性执行OnPropertyChanged（）方法，以便通知绑定并“刷新”文本。

    private string name;

    public string Name
    {
        get
        {
            return name;
        }
        set
        {
            if (name == value)
            {
                return;
            }
            name = value;
            OnPropertyChanged();
        }
    }

不要忘记更新Binding路径以使用属性而不是私有字段...（{Binding Name}）

点击列表视图

1 个答案: