Dreamine.MVVM.Generators

Dreamine.MVVM.Generators is a Roslyn incremental source generator package used by the Dreamine MVVM ecosystem.

This package generates MVVM boilerplate code at compile time based on declarative attributes.

The main attributes currently handled are:

• DreamineProperty
• DreamineEntry
• DreamineModel
• DreamineEvent
• DreamineCommand

The goal of this package is to reduce repetitive code while keeping generation rules and constraints explicit.

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What this package does

MVVM projects repeatedly need the following patterns:

• backing field → property exposure
• method → ICommand property generation
• model / event reference exposure
• application entry bootstrap generation
• declarative command forwarding generation

Dreamine.MVVM.Generators moves those repetitive patterns into the generation layer so ViewModel and App code can stay smaller.

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Key Features

• Built on Roslyn Incremental Source Generators
• Can be packaged as an analyzer package
• Generates code from Dreamine attributes
• Supports entry bootstrap generation
• Supports field-based auto wiring
• Supports DreamineCommand-based direct and forwarding command generation
• Can be packed into analyzers/dotnet/cs
• Supports automatic analyzer registration through buildTransitive

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Requirements

• Target Framework: netstandard2.0
• Usually used together with:
  • Dreamine.MVVM.Attributes
  • Dreamine.MVVM.Core
  • WPF / .NET MVVM applications

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Installation

Option A) NuGet

dotnet add package Dreamine.MVVM.Generators

Option B) PackageReference

<ItemGroup>
  <PackageReference Include="Dreamine.MVVM.Generators" Version="1.0.6" />
</ItemGroup>

This package is intended to be used as an analyzer package, and buildTransitive is the recommended way to register it automatically in consuming projects.

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Project Structure

Dreamine.MVVM.Generators
├── DreamineAutoWiringGenerator.cs
├── DreamineCommandSourceGenerator.cs
├── DreamineEntryGenerator.cs
├── AnalyzerReleases.Shipped.md
├── AnalyzerReleases.Unshipped.md
├── buildTransitive/
│   └── Dreamine.MVVM.Generators.targets
└── Dreamine.MVVM.Generators.csproj

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Architecture Role

This package belongs to the generation layer of the Dreamine MVVM stack.

ViewModel / App Source Code
        │
        ├─ Dreamine.MVVM.Attributes
        │     (markers / metadata)
        │
        ├─ Dreamine.MVVM.Generators
        │     (compile-time code generation)
        │
        └─ Dreamine.MVVM.Core
              (runtime MVVM infrastructure)

The responsibility split is:

• Attributes: declare intent
• Generators: emit source code
• Core: executes runtime behavior

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Supported Generators

1) DreamineEntryGenerator

Generates application bootstrap code for types marked with [DreamineEntry].

Current responsibilities

• Generates application startup initialization code
• Calls DMContainer.AutoRegisterAll(...)
• Calls ViewModelLocator.RegisterAll(...)
• Hooks FrameworkElement.Loaded to attach View ↔ ViewModel automatically
• Generates RegisterBefore, RegisterAfter, and ShowMainWindow partial hooks

Current constraints

• The target type must be partial
• The target type must inherit System.Windows.Application
• The design assumes only one valid entry type

Example

using Dreamine.MVVM.Attributes;

[DreamineEntry]
public partial class App : Application
{
}

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2) DreamineAutoWiringGenerator

Generates helper properties from fields marked with [DreamineProperty], [DreamineModel], and [DreamineEvent].

Current responsibilities

• _title → Title
• _model → Model
• _event → Event

Current behavior

• Handles field-based generation only
• Does not regenerate from property declarations
• Adds helper properties to a partial class
• Skips generation when a member name conflict already exists

Example

using Dreamine.MVVM.Attributes;

public partial class MainViewModel
{
    [DreamineProperty]
    private string _title;

    [DreamineModel]
    private MainModel _model;

    [DreamineEvent]
    private MainEvent _event;
}

Generated intent

• Title → field-backed property
• Model → model access property
• Event → event access property

Notes

• [DreamineProperty] generation assumes SetProperty(ref field, value) is available
  so the target type must provide SetProperty
• [DreamineModel] and [DreamineEvent] currently should not be used on readonly fields
• DreamineModel uses a new T() initialization path
• DreamineEvent uses a DMContainer.Resolve<T>() initialization path
• Generated code no longer forces inheritance from ViewModelBase

---

3) DreamineCommandSourceGenerator

Generates ICommand properties from methods marked with [DreamineCommand].

Current responsibilities

• Generates a {MethodName}Command property
• Supports CommandName override when provided
• Directly wraps the annotated method when TargetMethod is not specified
• Generates TargetMethod invocation code when forwarding is requested
• Assigns the result to the BindTo property when forwarding with a return value
• Generates a forwarding body when the method has no implementation body and TargetMethod is specified
• Avoids direct dependency on an external RelayCommand type by emitting an internal generated ICommand wrapper

Example

using Dreamine.MVVM.Attributes;

public partial class MainViewModel
{
    [DreamineCommand]
    private void Save()
    {
    }

    [DreamineCommand("Event.ReadmeClick", BindTo = "Readme")]
    partial void LoadReadme();
}

Current constraints

• The containing type must be partial
• The target method must be parameterless void
• Forwarding methods without a body must be partial
• Generation is skipped when the command property name conflicts with an existing member

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Quick Start

1) Add the required packages

<ItemGroup>
  <PackageReference Include="Dreamine.MVVM.Attributes" Version="1.0.6" />
  <PackageReference Include="Dreamine.MVVM.Core" Version="1.0.9" />
  <PackageReference Include="Dreamine.MVVM.Generators" Version="1.0.11" PrivateAssets="all" OutputItemType="Analyzer" />
</ItemGroup>

2) Declare attributes

using Dreamine.MVVM.Attributes;

public partial class MainViewModel
{
    [DreamineProperty]
    private string _title;

    [DreamineCommand]
    private void Save()
    {
    }

    [DreamineCommand("Event.ReadmeClick", BindTo = "Readme")]
    partial void LoadReadme();
}

3) Build

During build, partial source files are generated.

Typical outputs include:

• Title property
• SaveCommand
• LoadReadmeCommand
• forwarding method body

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Important Notes Based on the Current Code

1) The generator package is not a standalone runtime framework

Generated code still assumes some Dreamine runtime concepts exist.

Examples:

• DMContainer
• ViewModelLocator
• SetProperty

This package is intended to be used inside the Dreamine MVVM stack.

2) Not all attributes have the same usage scope

Under the current implementation:

• DreamineEntry → App / bootstrap layer
• DreamineProperty → ViewModel layer with SetProperty
• DreamineModel, DreamineEvent → field access generation
• DreamineCommand → method-based command generation

3) The generation rules are intentionally becoming stricter

The current generator implementations prioritize:

• partial type validation
• method signature validation
• name conflict prevention
• diagnostics for invalid usage

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Packaging Notes

The current project assumes analyzer-style packaging.

Typical configuration points are:

• PackageType=Analyzer
• OutputItemType=Analyzer
• IncludeBuildOutput=false
• package the generator DLL into analyzers/dotnet/cs
• use buildTransitive for automatic registration

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Comparison

Package	Role	Runtime Logic	Compile-Time Generation
Dreamine.MVVM.Attributes	declaration layer	No	No
Dreamine.MVVM.Generators	generation layer	No	Yes
Dreamine.MVVM.Core	runtime layer	Yes	No

This separation keeps the system layered by responsibility.

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Recommended Pairing

This package is usually used together with:

Dreamine.MVVM.Attributes
Dreamine.MVVM.Core
Dreamine WPF / UI / App packages

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License

MIT License