Wpf 绑定集合子属性更新

我在更新值时遇到问题​​使绑定成为ObservableCollection子属性的Listview的

我的主要视图模型

public class ClienteViewModel : ViewModelBase
    {
...
    public ContatoViewModel ContatoViewModel
    {
      get
      {
         contatoViewModel = new ContatoViewModel(db,ClienteSelecionado);
         return contatoViewModel;
      }
      set
      {
         this.contatoViewModel = value;
         RaisePropertyChanged("ContatoViewModel");
      }
   }
}

 public class ContatoViewModel : ViewModelBase
    {
      public ObservableCollection<Contato> Contatos{
           // list values 
           }

      public ICommand addContato{get;set;}

      public ICommand removeContato{get;set;}

      public Contato SelectedContato{get;set;}


    }
}

第二视图模型

public class ClienteViewModel : ViewModelBase
    {
...
    public ContatoViewModel ContatoViewModel
    {
      get
      {
         contatoViewModel = new ContatoViewModel(db,ClienteSelecionado);
         return contatoViewModel;
      }
      set
      {
         this.contatoViewModel = value;
         RaisePropertyChanged("ContatoViewModel");
      }
   }
}

 public class ContatoViewModel : ViewModelBase
    {
      public ObservableCollection<Contato> Contatos{
           // list values 
           }

      public ICommand addContato{get;set;}

      public ICommand removeContato{get;set;}

      public Contato SelectedContato{get;set;}


    }
}

公共类ContatoViewModel:ViewModelBase
{
公共可观测收集Contatos{
//列表值
}
公共ICommand addContato{get；set；}
公共ICommand removeContato{get；set；}
公共Contato SelectedContato{get；set；}
}
}

XAML：

或

或

价值观​​正常显示，但当我在中插入一些值并调用raisePropertyChanged ObservableCollection（）时，没有更新任何内容

但如果列表在ViewModel中，则主要功能正常。我应该怎么做才能使它与子客户一起工作

 <Grid DataContext="{Binding ContatoViewModel}">
  <ListView ItemsSource="{Binding Contatos,UpdateSourceTrigger=PropertyChanged}" >
 </Grid>