Catel.Fody is an add-in for Fody, an extensible tool for weaving .NET assemblies at compile time. It automatically rewrites simple auto-properties into full Catel dependency-property style properties, weaves argument checks, improves logging calls, and more — all without you having to write boilerplate code.

Features

Feature	Description
Property weaving	Rewrites auto-properties on ObservableObject, ModelBase, and ViewModelBase
Computed property notifications	Automatically raises PropertyChanged for calculated properties
Argument check weaving	Converts argument-check attributes into actual guard code
Logging weaving	Replaces LogManager.GetCurrentClassLogger() with the faster LogManager.GetLogger(typeof(...)) form
Exposed properties	Exposes model properties on a view model using [Expose]
Configuration	Fine-grained control over which features are enabled

Quick start

1. Install the NuGet package:

dotnet add package Catel.Fody

2. Ensure FodyWeavers.xml exists in your project and contains the <Catel /> element:

<?xml version="1.0" encoding="utf-8"?>
<Weavers>
  <Catel />
</Weavers>

The FodyWeavers.xml file is created automatically when you first install the Fody NuGet package. If it already exists, just add <Catel /> to it.

Disabling weaving for specific types, properties or methods

To prevent Catel.Fody from weaving a type, a specific property, or a method, decorate it with the [NoWeaving] attribute:

// Disable weaving for the entire class
[NoWeaving]
public class MyClass : ModelBase
{
    // ...
}

// Disable weaving for a single computed property
public class Person : ModelBase
{
    public string FirstName { get; set; }
    public string LastName { get; set; }

    [NoWeaving]
    public string FullName => $"{FirstName} {LastName}".Trim();
}

[NoWeaving] can also be applied to a parameterized On<PropertyName>Changed method to suppress the build warning that Catel.Fody emits when it finds such a method but cannot weave it. See Parameterized OnXChanged methods for details.

Weaving logging

Catel.Fody automatically converts calls to LogManager.GetCurrentClassLogger() into the slightly faster LogManager.GetLogger(typeof(ClassName)) form at compile time:

// Before weaving
private static readonly ILog Log = LogManager.GetCurrentClassLogger();

// After weaving (equivalent compiled output)
private static readonly ILog Log = LogManager.GetLogger(typeof(MyClass));

This is a transparent optimization; no source-code changes are required.