表单MVVM实现，通过OnAppraing事件填充XAML ListView

我有一个异步rest服务，当通过OnAppearing事件加载页面时，它会创建一个列表

protected async override void OnAppearing()
{
     base.OnAppearing();

     RestService restService = new RestService();
     List<Example> exampleList = await restService.GetExample();
}

protected async override void OnAppearing（）
{
base.OnAppearing（）；
RestService RestService=新的RestService（）；
List exampleList=等待restService.GetExample（）；
}

---

当异步操作准备好使用MVVM模式时，用exampleList填充XAML ListView的最佳实践是什么？

我个人提供了一个基本ContentPage实现，并在视图模型中实现了一个接口。例如

public interface IPageAppearingEvent
{
    void OnAppearing();
}

public class BasePage : ContentPage
{
    protected override void OnBindingContextChanged ()
    {
        base.OnBindingContextChanged ();

        var onAppearingLifeCycleEvents = BindingContext as IPageAppearingEvent;
        if (onAppearingLifeCycleEvents != null) {
            var lifecycleHandler = onAppearingLifeCycleEvents;

            base.Appearing += (object sender, EventArgs e) => lifecycleHandler.OnAppearing ();
        }
    }
}

public class ViewModel : IPageAppearingEvent
{
    public void OnAppearing()
    {
        //Do whatever you like in here
    }
}

---

只要您确保您的视图是BasePage的子类，那么您就可以开始了。

我个人提供了一个基本ContentPage实现，并且在视图模型中实现了一个接口。例如

public interface IPageAppearingEvent
{
    void OnAppearing();
}

public class BasePage : ContentPage
{
    protected override void OnBindingContextChanged ()
    {
        base.OnBindingContextChanged ();

        var onAppearingLifeCycleEvents = BindingContext as IPageAppearingEvent;
        if (onAppearingLifeCycleEvents != null) {
            var lifecycleHandler = onAppearingLifeCycleEvents;

            base.Appearing += (object sender, EventArgs e) => lifecycleHandler.OnAppearing ();
        }
    }
}

public class ViewModel : IPageAppearingEvent
{
    public void OnAppearing()
    {
        //Do whatever you like in here
    }
}

只要您确保您的视图是BasePage的子类，就可以继续了