c# - Xamarin 表格 "...DisplayAlert does not exist in the current context."

Question

我正在使用 Xamarin，对它还是个新手，但我遇到了一个问题，我觉得我不应该这样。这是我的问题:

using System;
using Xamarin.Forms;

namespace DataBinding_Lists
{
public class App
{
    public static Page GetMainPage ()
    {   
        var listView = new ListView { RowHeight = 40 };
        listView.ItemsSource = new Person []
        {
            new Person { FirstName = "Abe", LastName = "Lincoln" },
            new Person { FirstName = "Groucho", LastName = "Marks" },
            new Person { FirstName = "Carl", LastName = "Marks" },
        };

        listView.ItemTemplate = new DataTemplate(typeof(TextCell));
        listView.ItemTemplate.SetBinding(TextCell.TextProperty, "FirstName");
        listView.ItemSelected += async (sender, e) => {
            await DisplayAlert ("Tapped!", e.SelectedItem + " was tapped.", "OK", "");
        };

        return new ContentPage { 
            Content = new StackLayout
            {
                Padding = new Thickness (5,20,5,5),
                Spacing = 10,
                Children = { listView }
            }
        };
    }

}

显然，我在另一个名为“Person”的页面上有一个类。此类有两个属性:“FirstName”和“LastName”。当我尝试像在 Xamarin 中那样将所有这些放在一起时，我收到错误消息:“名称‘DisplayAlert’在当前上下文中不存在。”

Answer 1

或者只是尝试使用:

await App.Current.MainPage.DisplayAlert("Alert", "your message", "OK");