通过 Avalonia 上的模板绑定分配按钮单击事件

Question

我有一个模板化控件SoftwareReleaseControl，它显示一些文本和一个按钮。我需要此按钮从创建SoftwareReleaseControl控件时指定的属性OnInstallClick继承其Click事件。

问题是：我无法让它工作。它不绑定到模板的属性。我尝试将源代码从Avalonia的按钮(ClickEvent)复制到控件的代码隐藏。它显示为事件处理程序，但不会传递给按钮，并且还会给出Unable to find suitable setter or adder [...]错误。

SoftwareReleaseControl.xaml：

<Styles xmlns="https://github.com/avaloniaui"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:my="using:Updater.Controls">
<Design.PreviewWith>
<StackPanel Spacing="5">
<Panel Classes="Spacing"/>
<my:SoftwareReleaseControl Title="..." Version="..." Description="..." Installed="..."/>
<my:SoftwareReleaseControl Title="..." Version="..." Description="..." Installed="..."/>
</StackPanel>
</Design.PreviewWith>
<Style Selector="TextBlock">
<Setter Property="Foreground" Value="{DynamicResource text}"/>
<Setter Property="FontFamily" Value="Lato"/>
</Style>
[...]
<Style Selector="my|SoftwareReleaseControl">
[...]
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Panel Background="{TemplateBinding Background}"
HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
VerticalAlignment="{TemplateBinding VerticalAlignment}"
Height="{TemplateBinding Height}"
MinWidth="{TemplateBinding MinWidth}" Width="{TemplateBinding Width}">
<Grid Margin="{TemplateBinding Padding}"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
RowDefinitions="46, *, 40">
[...]
<StackPanel Grid.Row="2" Orientation="Horizontal">
======= HERE ===>>  <Button x:Name="PART_footer_installButton"
Content="Instalar"
======= PROBLEM ===>>       Click="{TemplateBinding OnInstallClick}">
<Button.Styles>
<Style Selector="Button#PART_footer_installButton">
<Setter Property="VerticalAlignment" Value="Bottom"/>
<Setter Property="HorizontalAlignment" Value="Left"/>
<Setter Property="Foreground" Value="{DynamicResource text}"/>
<Setter Property="FontSize" Value="16"/>
<Setter Property="Tag" Value="{TemplateBinding Tag}"/>
</Style>
<Style Selector="Button#PART_footer_installButton:pointerover /template/ ContentPresenter#PART_ContentPresenter">
<Setter Property="TextBlock.Foreground" Value="{DynamicResource text}"/>
</Style>
</Button.Styles>
</Button>
</StackPanel>
</Grid>
</Panel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Styles>

SoftwareReleaseControl.xaml.cs(代码隐藏)：

using Avalonia;
using Avalonia.Controls;
using Avalonia.Controls.Primitives;
using Avalonia.Interactivity;
using System;
namespace Updater.Controls
{
public partial class SoftwareReleaseControl : TemplatedControl
{
public SoftwareReleaseControl()
{

}
public static readonly RoutedEvent<RoutedEventArgs> OnInstallClickEvent = RoutedEvent.Register<Button, RoutedEventArgs>(nameof(OnInstallClick), RoutingStrategies.Bubble);
public event EventHandler<RoutedEventArgs> OnInstallClick
{
add => AddHandler(OnInstallClickEvent, value);
remove => RemoveHandler(OnInstallClickEvent, value);
}
[...]
}
}

MainWindow.xaml(我试图在其中显示控件)：

<Window xmlns="https://github.com/avaloniaui"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="using:Updater.ViewModels"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:my="using:Updater.Controls"
mc:Ignorable="d" Width="800" Height="520"
x:Class="Updater.Views.MainWindow"
Icon="/Assets/avalonia-logo.ico"
Title="Updater">
<Grid HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
Background="{DynamicResource window.background}"
RowDefinitions="40, *" ColumnDefinitions="*">
[...]
<ScrollViewer Grid.Row="1">
<StackPanel Spacing="5" x:Name="stk_releases">
<Panel Classes="Spacing"/>
==== HERE ===>> <my:SoftwareReleaseControl Title="..." Version="..." Description="..." Installed="..." OnInstallClick="{Binding btn_OnClick}"/>
<my:SoftwareReleaseControl Title="..." Version="..." Description="..." Installed="..." OnInstallClick="{Binding btn_OnClick}"/>
</StackPanel>
</ScrollViewer>
</Grid>
</Window>

我是否需要在 MainWindow 的代码隐藏或 ViewModel 中实现btn_OnClick并不重要。

当前代码给了我错误：

• Unable to find suitable setter or adder for property OnInstallClick of type Updater:Updater.Controls.SoftwareReleaseControl for argument Avalonia.Markup:Avalonia.Data.Binding, available setter parameter lists are: System.EventHandler[[Avalonia.Interactivity.RoutedEventArgs, Avalonia.Interactivity]]在 MainWindow.xaml上，在OnInstallClick="{Binding btn_OnClick}"上。
• Unable to find suitable setter or adder for property Click of type Avalonia.Controls:Avalonia.Controls.Button for argument Avalonia.Base:Avalonia.Data.IBinding, available setter parameter lists are: System.EventHandler1on *SoftwareReleaseControl.xaml*，在Click="{TemplateBinding OnInstallClick}"上。

是的，我确实在 App.xaml 上指定了样式包含。

为什么单击而不是命令：我需要发送方对象，以便我可以获取按钮的 Tag 属性。窗口上会有很多这样的控件，我需要整理出单击了哪一个。

tl;dr：如何在模板化控件上指定事件处理程序，以便其中的按钮可以继承处理程序作为其单击(而不是命令)。我需要在哪里实现处理程序？ViewModel 还是 CodeBehind？

Answer 1

我放弃了使用 Click，而是找到了一种将按钮本身发送到 Command 的方法。

SoftwareReleaseControl.xaml：

[...]
<Button x:Name="PART_footer_installButton"
Command="{Binding _OnInstallClick}"
CommandParameter="{Binding RelativeSource={RelativeSource Self}}">
<Button.Styles>
<Style Selector="Button#PART_footer_installButton">
<Setter Property="VerticalAlignment" Value="Bottom"/>
<Setter Property="HorizontalAlignment" Value="Left"/>
<Setter Property="Foreground" Value="{DynamicResource text}"/>
<Setter Property="FontSize" Value="16"/>
<Setter Property="Tag" Value="{TemplateBinding Tag}"/>
</Style>
<Style Selector="Button#PART_footer_installButton:pointerover /template/ ContentPresenter#PART_ContentPresenter">
<Setter Property="TextBlock.Foreground" Value="{DynamicResource text}"/>
</Style>
</Button.Styles>
</Button>
[...]

SoftwareReleaseControl.xaml.cs：

namespace Updater.Controls
{
public partial class SoftwareReleaseControl : TemplatedControl
{
public SoftwareReleaseControl()
{
DataContext = this;
}
public event EventHandler InstallClick;
private void _OnInstallClick(object? sender)
{
EventHandler handler = InstallClick;
handler?.Invoke(sender, EventArgs.Empty);
}
[...]
}
}

MainWindow.xaml.cs：

namespace Updater.Views
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainWindowViewModel(this);
for (int i = 0; i < 6; i++)
{
var t = new SoftwareReleaseControl();
t.Description = (string)App.Current.Resources["lorem.50"];
t.Installed = i % 2 == 0;
t.Tag = i;
t.InstallClick += T_InstallClick;
stk_releases.Children.Add(t);
}
}
private void T_InstallClick(object? sender, EventArgs e)
{
Debug.WriteLine("123");
if (sender is Button btn)
{
Debug.WriteLine(btn.Tag);
}
}
}
}