来自另一个类的ViewModel的Xamarin刷新集合

// ViewModel类
public class MyViewModel : INotifyPropertyChanged
{
    private ObservableCollection<string> myCollection;

    public ObservableCollection<string> MyCollection
    {
        get { return myCollection; }
        set
        {
            myCollection = value;
            OnPropertyChanged(nameof(MyCollection));
        }
    }

    public MyViewModel()
    {
        MyCollection = new ObservableCollection<string>();
    }

    public void RefreshCollection()
    {
        // 从数据源获取最新的数据
        List<string> newData = GetDataFromSource();

        // 清空集合
        MyCollection.Clear();

        // 将新数据添加到集合中
        foreach (string item in newData)
        {
            MyCollection.Add(item);
        }
    }

    // 实现INotifyPropertyChanged接口
    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

// 视图类
public class MyPage : ContentPage
{
    private MyViewModel viewModel;

    public MyPage()
    {
        viewModel = new MyViewModel();

        // 绑定集合到ListView
        ListView listView = new ListView();
        listView.SetBinding(ListView.ItemsSourceProperty, nameof(viewModel.MyCollection));

        // 刷新按钮
        Button refreshButton = new Button();
        refreshButton.Text = "Refresh";
        refreshButton.Clicked += (sender, e) =>
        {
            viewModel.RefreshCollection();
        };

        // 添加控件到页面
        Content = new StackLayout
        {
            Children = { listView, refreshButton }
        };
    }
}

// 在应用程序中使用视图
public class App : Application
{
    public App()
    {
        MainPage = new MyPage();
    }
}