PleasantUI 5.2.2

<img align="center" src="https://i.imgur.com/Sr3crB8.png">

PleasantUI

Repositories: Original (Onebeld) · Fork (ghudulf)

PleasantUI is a cross-platform UI theme and control library for Avalonia, inspired by Microsoft Fluent Design and the WinUI/UWP visual language. It completely re-styles every standard Avalonia control and adds a suite of custom controls, a multi-theme engine with custom theme support, a reactive localization system, and a custom window chrome — all AOT-compatible with no rd.xml required.

The project has been in active development since 2021, originally as part of the Regul and Regul Save Cleaner projects.

✨ Features

Complete Fluent-style control theming

Every standard Avalonia control gets a full Fluent Design makeover — rounded corners, layered fill colors, smooth pointer-over and pressed transitions, and accent color integration:

Custom Pleasant controls

Controls built from scratch that go beyond what Avalonia ships:

Control	Description	Demo
PleasantWindow	Custom window chrome with a Fluent title bar, subtitle, custom icon/title content, optional blur, content-extends-into-titlebar, and macOS caption override	None
NavigationView / NavigationViewItem	Collapsible side navigation panel, similar to WinUI NavigationView	None
PleasantTabView / PleasantTabItem	Chromium-style tab strip with add/close buttons and scrollable tab bar	None
ContentDialog	Modal overlay dialog with bottom button panel and smooth scroll content area	None
PleasantSnackbar	Temporary non-intrusive notification bar
ProgressRing	Circular progress indicator — both determinate and indeterminate with animated arc
OptionsDisplayItem	Settings-style row with header, description, icon, action button slot, navigation chevron, and expandable content
InformationBlock	Compact pill-shaped label combining an icon and a value
MarkedTextBox / MarkedNumericUpDown	Input controls with inline label/unit markers	None
RippleEffect	Material-style ripple click feedback
SmoothScrollViewer	ScrollViewer with inertia gesture support	None
PleasantMiniWindow	Lightweight floating window	None
Timeline	Displays a list of events in chronological order along a vertical axis. Supports four layout modes, custom icons, and five severity types.
InstallWizard	A multi-step installation wizard with a sidebar step list, progress bar, and Back / Next / Cancel navigation.
PleasantMenu	A customizable flyout menu with a title, optional info badges, a grid of large icon buttons, and a footer bar with small utility buttons.
PathPicker	Combines a read-only TextBox with a browse button. Supports OpenFile, SaveFile, and OpenFolder modes, optional multi-select, file-type filters, and two-way binding on the selected path text.
PopConfirm	Wraps any trigger control and shows a small popup with a header, body, and Confirm / Cancel buttons before executing a command.

Theme engine

• Built-in themes: Light, Dark, Mint, Strawberry, Ice, Sunny, Spruce, Cherry, Cave, Lunar
• System mode — follows the OS light/dark preference automatically
• Custom themes — create, edit, export, import, and persist your own color palettes via the built-in ThemeEditorWindow
• Accent color follows the OS accent or can be overridden per-user; light/dark variants and gradient pairs are generated automatically
• Settings are persisted to disk automatically on desktop; mobile apps can save manually

Localization system

• Localizer singleton backed by .NET ResourceManager — add any number of .resx resource files
• {Localize Key} AXAML markup extension binds reactively — switching language updates every bound string instantly without reloading views
• Localizer.TrDefault(key, fallback) for safe lookups that fall back to a raw string instead of an error message
• LocalizationChanged event for view models and code-behind to react to language switches

Packages

📖 Documentation

Detailed reference docs for each control are in the docs/ folder:

🚀 Getting Started

Install

Package List (Avalonia 12)

Published on NuGet:

<PackageReference Include="PleasantUI" Version="5.2.0" />
<PackageReference Include="PleasantUI.DataGrid" Version="5.2.0" />
<PackageReference Include="PleasantUI.MaterialIcons" Version="5.2.0" />
<PackageReference Include="PleasantUI.ToolKit" Version="5.2.0" />

Add the theme

In your App.axaml, add PleasantTheme to your styles:

<Application xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             x:Class="YourApp.App">
    <Application.Styles>
        <PleasantTheme />
    </Application.Styles>
</Application>

Initialize correctly

Make sure AvaloniaXamlLoader.Load(this) is called in Initialize():

public partial class App : Application
{
    public override void Initialize()
    {
        AvaloniaXamlLoader.Load(this); // required
    }

    public override void OnFrameworkInitializationCompleted()
    {
        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
        {
            desktop.MainWindow = new MainWindow
            {
                DataContext = new MainWindowViewModel(),
            };
        }

        base.OnFrameworkInitializationCompleted();
    }
}

Use PleasantWindow

Replace Window with PleasantWindow to get the custom Fluent title bar:

using PleasantUI.Controls;

public partial class MainWindow : PleasantWindow
{
    public MainWindow() => InitializeComponent();
}

<PleasantWindow 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"
                mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
                x:Class="YourApp.Views.MainWindow"
                Title="Avalonia Application">
</PleasantWindow>

Key PleasantWindow properties:

🌍 Localization

Register your .resx resource managers in your Application constructor:

public App()
{
    Localizer.AddRes(new ResourceManager(typeof(Properties.Localizations.App)));
    Localizer.ChangeLang("en");
}

Use {Localize Key} in AXAML — updates live when the language changes:

<TextBlock Text="{Localize WelcomeMessage}" />
<Button Content="{Localize SaveButton}" />

Switch language at runtime:

Localizer.ChangeLang("ru");

Safe lookup with fallback in code-behind:

string title = Localizer.TrDefault("DialogTitle", "Confirm");

🔲 Button variants

<Button Content="Default" />
<Button Theme="{DynamicResource AccentButtonTheme}" Content="Accent" />
<Button Theme="{DynamicResource DangerButtonTheme}" Content="Danger" />
<Button Theme="{DynamicResource AppBarButtonTheme}" Content="AppBar" />

📃 OptionsDisplayItem

<OptionsDisplayItem Header="Account"
                    Description="Manage your account"
                    Icon="{x:Static MaterialIcons.AccountOutline}"
                    Navigates="True" />


<OptionsDisplayItem Header="Dark mode"
                    Icon="{x:Static MaterialIcons.WeatherNight}">
    <OptionsDisplayItem.ActionButton>
        <ToggleSwitch />
    </OptionsDisplayItem.ActionButton>
</OptionsDisplayItem>


<OptionsDisplayItem Header="Advanced" Expands="True">
    <OptionsDisplayItem.Content>
        <StackPanel>
            <CheckBox Content="Enable feature X" />
        </StackPanel>
    </OptionsDisplayItem.Content>
</OptionsDisplayItem>

🖼️ Screenshots

Regul Save Cleaner

OlibKey

❤️ Credits

• Avalonia
• Some controls inspired by PieroCastillo's Aura.UI
• ProgressRing by ymg2006
• Built with JetBrains Rider

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