Stephane Delcroix StephaneDelcroix

BrewBuddy Session State

Project Overview

A .NET MAUI iOS app ("BrewBuddy") to control a Jura E8 coffee machine via Bluetooth, track coffee beans, brew history, and preferences, with AI-powered recommendations using Microsoft.Extensions.AI and AppleIntelligenceChatClient. Fun coffee-themed color scheme.

Architecture

.NET 10 MAUI targeting net10.0-ios and net10.0-maccatalyst
CommunityToolkit.Mvvm for [ObservableProperty] and [RelayCommand]
SQLite via sqlite-net-pcl for local persistence
Plugin.BLE v3 for Bluetooth LE

XAML Diffing Engine — Test Catalog

Tests for XamlNodeDiff.ComputeDiff(), the build-time diff engine that compares two XAML node trees and produces a change set of property changes (set/clear) and child list mutations (add/remove/reorder).

All XAML snippets are wrapped in <ContentPage xmlns="..." x:Class="Test.MyPage">…</ContentPage>. The Diff block shows the exact ToDebugString() output where available.

1 · Identical trees

Spec: XAML Incremental Hot Reload via XSG (XAML Source Generation)

Source: Loop document "Xaml (incremental) HotReload on XSG"

Objective

Leverage Roslyn XAML Source Generation (XSG) to implement incremental XAML Hot Reload (XHR) by deferring work to C# Hot Reload. This improves consistency, testability, supportability, and performance, and reduces maintenance overhead.

Lazy ResourceDictionary Specification

Problem

Slow inflation time: All resources are instantiated upfront during XAML inflation, even if never used
No x:Shared support: Resources that need parenting (e.g., StrokeShape) cannot be StaticResources because the same instance is shared - causing crashes when multiple elements try to parent the same object

Proposed Solution

Store Func<object> factories instead of object instances in ResourceDictionary. Resources are created on-demand when accessed.

XAML C# Expressions

Overview

XAML C# Expressions allow writing C# expressions directly in XAML attribute values. The source generator parses these expressions and generates appropriate bindings or event handlers.

Motivation

Currently, XAML property values can be:

Literal strings - Text="Hello World"

	using Microsoft.Maui.LifecycleEvents;
	#if __IOS__
	using System.Runtime.InteropServices;
	using UIKit;
	using Foundation;
	#endif

	namespace Maui.Controls.Sample;

	public static class MauiProgram

	<?xml version="1.0" encoding="UTF-8"?>
	<ContentPage
	xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
	xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
	x:Class="Microsoft.Maui.Controls.Xaml.UnitTests.LazyResourceDictionary">
	<ContentPage.Resources>
	<Color x:Key="PrimaryColor">Blue</Color>
	<Thickness x:Key="StandardPadding">10</Thickness>
	<Style x:Key="MyLabelStyle" TargetType="Label">
	<Setter Property="TextColor" Value="{StaticResource PrimaryColor}"/>

	//------------------------------------------------------------------------------
	// <auto-generated>
	// This code was generated by a .NET MAUI source generator.
	//
	// Changes to this file may cause incorrect behavior and will be lost if
	// the code is regenerated.
	// </auto-generated>
	//------------------------------------------------------------------------------
	#nullable enable
	#pragma warning disable CS0219 // Variable is assigned but its value is never used

	//------------------------------------------------------------------------------
	// <auto-generated>
	// This code was generated by a .NET MAUI source generator.
	//
	// Changes to this file may cause incorrect behavior and will be lost if
	// the code is regenerated.
	// </auto-generated>
	//------------------------------------------------------------------------------
	#nullable enable
	#pragma warning disable CS0219 // Variable is assigned but its value is never used

	//------------------------------------------------------------------------------
	// <auto-generated>
	// This code was generated by a .NET MAUI source generator.
	//
	// Changes to this file may cause incorrect behavior and will be lost if
	// the code is regenerated.
	// </auto-generated>
	//------------------------------------------------------------------------------
	#nullable enable
	#pragma warning disable CS0219 // Variable is assigned but its value is never used