我的XAML文件的ListView正在填充一个ViewModel，该ViewModel具有来自服务的ObservableCollection，但ListView没有显示信息。我已经检查了服务是否返回正确的信息。
这是我的XML文件的代码：

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="XAMLUnit1.Views.NetflixRoulettePage" Title="Movie">
    <ContentPage.Content>
         <StackLayout>
         <AbsoluteLayout>
                <BoxView Color="Gray"  AbsoluteLayout.LayoutFlags="All" AbsoluteLayout.LayoutBounds="0,0,1,1"></BoxView>
                <SearchBar x:Name="searchBar"
                           Placeholder="Search By Actor's name" 
                           PlaceholderColor="White"
                           AbsoluteLayout.LayoutFlags="All"
                           AbsoluteLayout.LayoutBounds="0.1,0.1,1,1"  SearchCommand="{Binding SearchMovieCommand}" ></SearchBar>
            </AbsoluteLayout>

       <ListView  x:Name="ListOfMovies"  
            ItemsSource="{ Binding MovieList}" >
            <ListView.ItemTemplate>
                    <DataTemplate>
                        <ViewCell>
                            <StackLayout>
                                <ImageCell 
                                        ImageSource="{Binding poster_path, StringFormat='https://image.tmdb.org/t/p/w500{0}'}">
                                </ImageCell>
                                    <StackLayout Orientation="Horizontal">
                                    <TextCell Detail="{Binding title}"></TextCell>
                                    <TextCell Detail="{Binding release_date}"></TextCell>
                                </StackLayout>
                            </StackLayout>
                        </ViewCell>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
        </StackLayout>
    </ContentPage.Content>
</ContentPage>

字符串
这是调用服务的ViewModel，它使用其ObservableCollection作为ListView的ItemsSource：

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
using Xamarin.Forms;
using XAMLUnit1.Models;
using XAMLUnit1.ServiceImpl;
using XAMLUnit1.Services;

namespace XAMLUnit1.ViewModels
{
  public  class MovieRouletteViewModel
    {
        IMovieService service;
        public ObservableCollection<Movie> MovieList { get; set; }
        public ICommand SearchMovieCommand { get; set; }
        public MovieRouletteViewModel()
        {
            service = new MovieServiceFinder();
            SearchMovieCommand = new Command(GetMovies);
        }

        private void  GetMovies()
        { var list= service.GetMovies("");
            MovieList = list;

        }

    }
}



public partial class NetflixRoulettePage : ContentPage
    {
        MovieRouletteViewModel viewModel;
        public NetflixRoulettePage()
        {
            InitializeComponent();
            viewModel = new MovieRouletteViewModel();
            BindingContext = viewModel;

        }


        private void SearchBar_TextChanged(object sender, TextChangedEventArgs e)
        {
        }
    }

型