Catel

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Catel is an application development platform with the focus on MVVM (WPF).

For documentation, please visit the documentation portal

Features and components

Below are a few features that are available in Catel.

Catel.Core

Catel.Core is the library you want to include in all your projects, whether you are writing a UI project or not. It contains lots of useful helper methods. The most important features are listed below:

Argument validation (e.g. Argument.IsNotNull(() => myArgument))
Caching
Data (ModelBase, PropertyBag, Validation)
Messaging
Reflection (same reflection API for every supported platform)
Weak references (WeakEventListener)

And more....

Catel.MVVM

Catel.MVVM is the library you want to include when you are writing a WPF UI project and you want to use the MVVM pattern. Catel provides context-aware view and view-model creation, which can be used to solve the nested user controls problem.

The most important features are listed below:

Auditing
Collections (FastObservableCollection)
Commands (Command, TaskCommand, etc)
Converters (tons of converters out of the box)
Services
- MessageService
- NavigationService
- OpenFileService
- BusyIndicatorService
- SaveFileService
- UIVisualizerService
View models
- Automatic validation
- Automatic mappings from model to view model
Views
- DataWindow
- UserControl
- Window

Example code

Models

This model has automatic change notifications and validation.

public class Person : ValidatableModelBase
{
    public string FirstName { get; set; }

    public string LastName { get; set; }

    protected override void ValidateFields(List<IFieldValidationResult> validationResults)
    {
        if (string.IsNullOrWhitespace(FirstName))
        {
            validationResults.Add(FieldValidationResult.CreateError(nameof(FirstName), "First name is required"));
        }

        if (string.IsNullOrWhitespace(LastName))
        {
            validationResults.Add(FieldValidationResult.CreateError(nameof(LastName), "Last name is required"));
        }
    }    
}

View models

This is a view model with:

Automatic injection of the DataContext
Automatic mapping of properties & validation from model => view model

public class PersonViewModel : ViewModelBase
{
    public PersonViewModel(Person person)
    {
        Argument.IsNotNull(() => person);

        Person = person;
    }

    [Model]
    private Person Person { get; set; }

    [ViewModelToModel]
    public string FirstName { get; set; }

    [ViewModelToModel]
    public string LastName { get; set; }
}

How to contribute

Support on Open Collective

Please consider supporting Catel on Open Collective.

Translating

To add translations to Catel, the Multilingual App Toolkit (MAT) is required.

Download the MAT Editor
Open your specific language (or create it) in the MultilingualResources folder, e.g. ./src/Catel.MVVM/MultilingualResources/Catel.MVVM.nl.xlf
Edit the xlf file and create a pull request (PR) with only this file

Building Catel

Prerequisites

Catel requires Visual Studio 2022 to compile successfully. You also need to ensure you have the following features installed:

Note that the .vsconfig in the src root should notify about missing components when opening the solution.

Note that you should run these commands using powershell in the root of the repository.

Running a build

.\build.ps1 -target build

Running a build with unit tests

.\build.ps1 -target buildandtest

Running a build with local packages

Note that this assumes a local packages directory at C:\Source\_packages, which can be added to the NuGet feeds:

.\build.ps1 -target buildandpackagelocal

WPF components based on Catel

If you are planning on using WPF, there is a huge set (60+) of free open-source components available based on Catel. All these open source are developed by a company called WildGums (see https://www.wildgums.com) and provided to the community for free. The components are well maintained and being used in several commercial WPF applications.

For more information, see https://github.com/wildgums