Using generated entities

After generating code from Home Assistant with nd-codegen you can use a strongly typed API to work with entities in Home Assistant. The Entities can be injected into your app like this:

[NetDaemonApp]
class MyApp
{
    public MyApp(Entities entities)
    {
        LightEntity livingRoomLight = entities.Light.LivingRoomLight;
        // ..
    }
}

Entities is a generated class that provides access to all your entities in Home Assistant. The object returned by Entities.Light.LivingRoomLight is of type LightEntity which is also generated. This specific instance represents the light.living_room_light entity in Home Assistant.

It is also possible to directly inject eg the LightEntities class

[NetDaemonApp]
class MyApp
{
    public MyApp(LightEntities lightEntities)
    {
        LightEntity livingRoomLight = lightEntities.LivingRoomLight;
        // ..    
    }
}

note

To inject the generated types, make sure you call AddHomeAssistantGenerated() in your startup code.

Alternatively you can create an instance of the generated Entities class via its constructor that takes the IHaContext.

_myEntities = new Entities(haContext);

// ..

LightEntity livingRoomLight = _myEntities.Light.LivingRoomLight;

The LightEntity class provides strongly typed access to the state and attributes of the entity like:

if (livingRoomLight.State == "on" && livingRoomLight.Attributes.Brightness > 100) // ...

tip

You can also check for "on" or "off" states using the Extension Methods IsOn() and IsOff()

It also allows you to respond to state change events of the entity via the StateAllChanges and StateChanges methods.

kitchenLight.StateAllChanges()
    .Where(s => s.Old?.Attributes?.Brightness < 128 
             && s.New?.Attributes?.Brightness >= 128)
    .Subscribe(e => HandleBrightnessUp());

The code generator will create a class for each domain in Home Assistant that has entities. As an example, for the climate domain there is a class ClimateEntity and for the sensor domain there is a class SensorEntity. These classes all derive from the built-in base class Entity<TEntity, TEntityState, TAttributes>.