chore: add avalonia DataValidationErrors demo.

Author: NaBian

src/Avalonia/HandyControlDemo_Avalonia/App.axaml.cs

@@ -1,4 +1,5 @@
 using System.Globalization;
+using System.Linq;
 using Avalonia;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Data.Core.Plugins;
@@ -17,7 +18,7 @@ public override void Initialize()
     public override void OnFrameworkInitializationCompleted()
     {
         Properties.Langs.Lang.Culture = new CultureInfo("en");
-        BindingPlugins.DataValidators.RemoveAt(0);
+        RemoveDefaultDataValidator();
 
         if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
         {
@@ -26,4 +27,17 @@ public override void OnFrameworkInitializationCompleted()
 
         base.OnFrameworkInitializationCompleted();
     }
+
+    private static void RemoveDefaultDataValidator()
+    {
+        // Get an array of plugins to remove
+        var dataValidationPluginsToRemove =
+            BindingPlugins.DataValidators.OfType<DataAnnotationsValidationPlugin>().ToArray();
+
+        // remove each entry found
+        foreach (var plugin in dataValidationPluginsToRemove)
+        {
+            BindingPlugins.DataValidators.Remove(plugin);
+        }
+    }
 }

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/TextBoxDemo.axaml

@@ -1,12 +1,9 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
-             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              xmlns:hc="https://handyorg.github.io/handycontrol"
-             mc:Ignorable="d"
-             d:DesignWidth="800"
-             d:DesignHeight="450"
-             x:Class="HandyControlDemo.UserControl.TextBoxDemo">
+             xmlns:vm="clr-namespace:HandyControlDemo.ViewModel"
+             x:Class="HandyControlDemo.UserControl.TextBoxDemo"
+             DataContext="{Binding InputElementDemo, Source={x:Static vm:ViewModelLocator.Instance}}">
     <ScrollViewer>
         <hc:UniformSpacingPanel Spacing="32"
                                 Margin="32"
@@ -32,6 +29,7 @@
                          Text="This is the content"
                          IsEnabled="False" />
                 <TextBox Watermark="please enter email"
+                         Text="{Binding Email1, UpdateSourceTrigger=PropertyChanged}"
                          hc:TitleElement.Title="This item must be filled in"
                          Theme="{StaticResource TextBoxExtend}"
                          hc:InfoElement.Necessary="True"
@@ -44,6 +42,7 @@
                          Margin="0,32,0,0"
                          Text="This is the content" />
                 <TextBox Width="380"
+                         Text="{Binding Text1, UpdateSourceTrigger=PropertyChanged}"
                          hc:TitleElement.TitleWidth="120"
                          Watermark="Please enter content"
                          hc:TitleElement.TitlePlacement="Left"
@@ -75,6 +74,7 @@
                          Text="This is the content"
                          IsEnabled="False" />
                 <TextBox Watermark="please enter email"
+                         Text="{Binding Email2, UpdateSourceTrigger=PropertyChanged}"
                          hc:TitleElement.Title="This item must be filled in"
                          Theme="{StaticResource TextBoxExtend.Small}"
                          hc:InfoElement.Necessary="True"
@@ -87,6 +87,7 @@
                          Margin="0,32,0,0"
                          Text="This is the content" />
                 <TextBox Width="380"
+                         Text="{Binding Text2, UpdateSourceTrigger=PropertyChanged}"
                          hc:TitleElement.TitleWidth="120"
                          Watermark="Please enter content"
                          hc:TitleElement.TitlePlacement="Left"

src/Avalonia/HandyControlDemo_Avalonia/ViewModel/Common/InputElementDemoViewModel.cs

@@ -0,0 +1,19 @@
+using System.ComponentModel.DataAnnotations;
+using CommunityToolkit.Mvvm.ComponentModel;
+
+namespace HandyControlDemo.ViewModel;
+
+public partial class InputElementDemoViewModel : ObservableValidator
+{
+    [Required] [EmailAddress] [ObservableProperty] [NotifyDataErrorInfo]
+    private string? _email1;
+
+    [Required] [EmailAddress] [ObservableProperty] [NotifyDataErrorInfo]
+    private string? _email2;
+
+    [Required] [ObservableProperty] [NotifyDataErrorInfo]
+    private string? _text1;
+
+    [Required] [ObservableProperty] [NotifyDataErrorInfo]
+    private string? _text2;
+}

src/Avalonia/HandyControlDemo_Avalonia/ViewModel/DemoViewModelBase`1.cs

@@ -3,13 +3,7 @@
 
 namespace HandyControlDemo.ViewModel;
 
-public class DemoViewModelBase<T> : ObservableObject
+public partial class DemoViewModelBase<T> : ObservableObject
 {
-    private IList<T> _dataList = [];
-
-    public IList<T> DataList
-    {
-        get => _dataList;
-        set => SetProperty(ref _dataList, value);
-    }
+    [ObservableProperty] private IList<T> _dataList = [];
 }

src/Avalonia/HandyControlDemo_Avalonia/ViewModel/ViewModelLocator.cs

@@ -19,9 +19,12 @@ private ViewModelLocator()
 
         services.AddSingleton<DataService>();
         services.AddTransient<MainViewModel>();
+        services.AddTransient<InputElementDemoViewModel>();
 
         _serviceProvider = services.BuildServiceProvider();
     }
 
     public MainViewModel Main => _serviceProvider.GetService<MainViewModel>()!;
+
+    public InputElementDemoViewModel InputElementDemo => _serviceProvider.GetService<InputElementDemoViewModel>()!;
 }

src/Avalonia/HandyControl_Avalonia/Themes/Styles/DataValidationErrors.axaml

@@ -0,0 +1,50 @@
+<ResourceDictionary xmlns="https://github.com/avaloniaui"
+                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+    <ControlTheme x:Key="{x:Type DataValidationErrors}"
+                  TargetType="DataValidationErrors">
+        <Setter Property="Template">
+            <ControlTemplate>
+                <DockPanel LastChildFill="True">
+                    <ContentControl x:DataType="DataValidationErrors"
+                                    Content="{Binding (DataValidationErrors.Errors)}"
+                                    ContentTemplate="{TemplateBinding ErrorTemplate}"
+                                    DataContext="{TemplateBinding Owner}"
+                                    DockPanel.Dock="Right"
+                                    IsVisible="{Binding (DataValidationErrors.HasErrors)}" />
+                    <ContentPresenter Name="PART_ContentPresenter"
+                                      Padding="{TemplateBinding Padding}"
+                                      Background="{TemplateBinding Background}"
+                                      BorderBrush="{TemplateBinding BorderBrush}"
+                                      BorderThickness="{TemplateBinding BorderThickness}"
+                                      Content="{TemplateBinding Content}"
+                                      ContentTemplate="{TemplateBinding ContentTemplate}"
+                                      CornerRadius="{TemplateBinding CornerRadius}" />
+                </DockPanel>
+            </ControlTemplate>
+        </Setter>
+        <Setter Property="ErrorTemplate">
+            <DataTemplate>
+                <Canvas Width="16"
+                        Height="16"
+                        Margin="4,0,1,0"
+                        Background="Transparent">
+                    <Canvas.Styles>
+                        <Style Selector="ToolTip">
+                            <Setter Property="BorderBrush"
+                                    Value="{DynamicResource DangerBrush}" />
+                        </Style>
+                    </Canvas.Styles>
+                    <ToolTip.Tip>
+                        <ItemsControl x:DataType="DataValidationErrors"
+                                      ItemsSource="{Binding}" />
+                    </ToolTip.Tip>
+                    <Path Data="{StaticResource WarningGeometry}"
+                          Width="16"
+                          Height="16"
+                          Fill="{DynamicResource DangerBrush}"
+                          Stretch="Uniform" />
+                </Canvas>
+            </DataTemplate>
+        </Setter>
+    </ControlTheme>
+</ResourceDictionary>