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# AddCommandHandler\<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13>(IActionRegistration,string

Method in [ActionRegistrationExtension](/api/csharp/yarn.unity/yarn.unity.actionregistrationextension.md)

## Summary

Adds a command handler. Dialogue will pause execution after the command is called.

```csharp
public static void AddCommandHandler<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13>(this IActionRegistration registration, string commandName, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, Coroutine> handler);
```

## Remarks

When this command handler has been added, it can be called from your Yarn scripts like so:

```
<<commandName param1 param2>>
```

If `handler` is a method that returns a `UnityEngine.Coroutine`, when the command is run, the [DialogueRunner](/api/csharp/yarn.unity/yarn.unity.dialoguerunner.md) will wait for the returned coroutine to stop before delivering any more content.

If `handler` is a method that returns an `System.Collections.IEnumerator`, when the command is run, the [DialogueRunner](/api/csharp/yarn.unity/yarn.unity.dialoguerunner.md) will start a coroutine using that method and wait for that coroutine to stop before delivering any more content.

## Parameters

| Name                                                                                                    | Description                                                                                                    |
| ------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------- |
| `string` commandName                                                                                    | The name of the command.                                                                                       |
| `Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, Coroutine>` handler                       | The [CommandHandler](/api/csharp/yarn/yarn.commandhandler.md) that will be invoked when the command is called. |
| [Yarn.Unity.IActionRegistration](/api/csharp/yarn.unity/yarn.unity.iactionregistration.md) registration |                                                                                                                |