我正在测试 Avalonia 通知(C#、Windows 10、Visual Studio Community 2019)。每当我按下按钮并更改属性“问候”时,以下代码就会崩溃。
我想问题是图片中的注释所指示的。问题是如何避免这种情况?更改 Greeting 属性的内容后如何显示通知?这是代码:
using Avalonia;
using Avalonia.Controls;
using Avalonia.Interactivity;
using Avalonia.Markup.Xaml;
using Avalonia.Controls.Notifications;
using System;
namespace Avalonia_test_Notifications.Views
{
public partial class MainWindow : Window
{
public ViewModels.MainWindowViewModel ViewModel;
public WindowNotificationManager Manager;
public MainWindow()
{
InitializeComponent();
this.DataContext = ViewModel;
#if DEBUG
this.AttachDevTools();
#endif
}
private void InitializeComponent()
{
AvaloniaXamlLoader.Load(this);
Manager = new WindowNotificationManager(this);
ViewModel = new ViewModels.MainWindowViewModel(Manager);
}
private void ShowNotification(object sender, RoutedEventArgs e)
{
ViewModel.ClickEvent(sender, e);
}
}
}
和
using System;
using System.Collections.Generic;
using System.Text;
using ReactiveUI;
using System.Reactive;
namespace Avalonia_test_Notifications.ViewModels
{
public class MainWindowViewModel : ViewModelBase
{
private string _greeting = "Greetings";
public string Greeting
{
get => _greeting;
set
{
this.RaiseAndSetIfChanged(ref _greeting, value);
}
}
public Avalonia.Controls.Notifications.Notification Notification;
public Avalonia.Controls.Notifications.IManagedNotificationManager Manager;
public string [] stringArray;
public MainWindowViewModel(Avalonia.Controls.Notifications.IManagedNotificationManager manager)
{
stringArray = new string[3] { "message 1", "message 2", "message 3" };
Manager = manager;
this.WhenAnyValue(x => x.Greeting).Subscribe(x=>ShowNotification(x));
}
public void ClickEvent(object sender, Avalonia.Interactivity.RoutedEventArgs e)
{
System.Random rand = new System.Random();
int x = rand.Next(0, 3);
Greeting = stringArray[x];
}
public void ShowNotification(string s)
{
Notification = new Avalonia.Controls.Notifications.Notification("TestNotification", s, Avalonia.Controls.Notifications.NotificationType.Information, TimeSpan.FromSeconds(0));
Manager.Show(Notification);
}
}
}
最后:
<Window xmlns="https://github.com/avaloniaui"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="using:Avalonia_test_Notifications.ViewModels"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
x:Class="Avalonia_test_Notifications.Views.MainWindow"
Icon="/Assets/avalonia-logo.ico"
Title="Avalonia_test_Notifications">
<Design.DataContext>
<vm:MainWindowViewModel/>
</Design.DataContext>
<StackPanel Orientation="Vertical">
<TextBlock Text="{Binding Greeting}" HorizontalAlignment="Center" VerticalAlignment="Center"/>
<Button Content="Notification" Click="ShowNotification"></Button>
</StackPanel>
</Window>