.net API响应返回null错误. NET MAUI

我正在try 从Unsplash获取一个API来显示图像

然而，我无法显示它们，因为错误CS1579声明:Getting error foreach statement cannot operating on type Root的变量，因为根不包含一个公共定义的'GetEnumerator'.

using Newtonsoft.Json;

namespace ImageAPI
{
    public partial class MainPage : ContentPage
    {
        int count = 0;
        private List<String> lst;
        private object usrName;

        public MainPage()
        {
            InitializeComponent();
            lst = new List<String>();
            BindingContext = this;
        }

        private async void OnCounterClicked(object sender, EventArgs e)
        {
            HttpClient client = new HttpClient();
            var url = "https://api.unsplash.com/search/photos/?page=1&query=office&client_id=R62b2dZL9UoHcYhxook8WAkwklTUcBHqhJEmxe5AEqY";
            try
            {
                HttpResponseMessage response = await client.GetAsync(url);
                var content = await response.Content.ReadAsStringAsync();
                var apiResponse = JsonConvert.DeserializeObject<Root>(content);

                if (response.IsSuccessStatusCode)
                {
                    if (apiResponse != null) {
                        foreach (var photo in apiResponse)
                        {
                            var username = photo.User?.Username;
                           
                             lst.Add(username);
                        }
                        imageListView.ItemsSource = lst;
                    }
                }
                else
                {
                    await DisplayAlert("Error", "Invalid response", "Ok");
                }
            }
            catch (Exception ex)
            {
                await DisplayAlert("Exception", $"{ex.Message}", "Ok");
            }
        }
    }
}

列表视图因此没有更新，没有显示任何内容！

感谢帮助！