# Using Acss

{% hint style="info" %}
**NOTE**

If there is no need for custom extensions, you can use Acss by following the examples on this page. 

This page provides the most basic examples of Acss usage. For other complex usage or customisation scenarios, please refer to the other chapters within this section.
{% endhint %}

## Installation

```bash
dotnet add package Nlnet.Avalonia.Css --version 1.0.0-beta.4
```

## Registering Acss and Type Resolution

This process can also be deferred until the initialisation is done together.

{% hint style="danger" %}
The current version does not support the use of multiple AcssContexts, only the default AcssContext.Default.
{% endhint %}

```csharp
private static AppBuilder BuildAvaloniaApp()
{
    return AppBuilder.Configure<App>()
        ...
        
        // Use avalonia css stuff.
        .UseAcssDefaultContext()
        
        // Type resolver for 'Your.Lib'. The GenericTypeResolver<TSink> will load all
        // types those belong to the assembly who contains the T class.
        .WithTypeResolverForAcssDefaultContext(new GenericTypeResolver<TSink>())
        ;
}
```

## Initializing AcssContext

You can do this optionally in the Application.Initialize() function. Of course, other timing is not affected.

* Use Acss.&#x20;
* Configuration Parameters.&#x20;
* Registering Types to the Type Interpretation Service.&#x20;
* Create a Rider configuration. If you are using Rider as a development tool.&#x20;
* Load the Acss source.

At this point, Acss is normally in effect.

```csharp
private class void Initialize()
{
    ...
    
    // [Optional] Use default css builder. It has same effect to 
    // AcssExtension.UseAvaloniaCssDefaultBuilder().
    AcssContext.UseDefaultContext();
	
    // [Optional] Set the current accent and other settings.
    var cfg = AcssContext.Default.GetService<IAcssConfiguration>();
    cfg.Accent = "blue";
    cfg.EnableTransitions = true;
    
    // [Optional] Create rider settings for this Acss builder.
    var riderBuilder = AcssContext.Default.GetService<IRiderSettingsBuilder>();
    riderBuilder.TryBuildRiderSettingsForAcss(out _, out _, null);
    
    // Load acss files to Application.Current.Styles. 
    // You can keep the acssFile for more operations.
    var loader = AcssContext.Default.GetService<IAcssLoader>();
    var acssFile = loader.Load(Application.Current.Styles, new FileSource("Acss/Case.acss"));
    
    // Or load acss files from a folder.
    loader.LoadCollection(Application.Current.Styles, new FileSourceCollection("Acss/"));
    
    ...
}
```