# DockerfileBuilderCallbackAnnotation Methods

- Package: [Aspire.Hosting](/reference/api/csharp/aspire.hosting.md)
- Type: [DockerfileBuilderCallbackAnnotation](/reference/api/csharp/aspire.hosting/dockerfilebuildercallbackannotation.md)
- Kind: `Methods`
- Members: `1`

Represents an annotation for providing callbacks to programmatically modify Dockerfile builds.

## AddCallback(Func<DockerfileBuilderCallbackContext, Task>)

> **Experimental:** ASPIREDOCKERFILEBUILDER001 - [Learn more](/diagnostics/aspiredockerfilebuilder001/)

- Name: `AddCallback(Func<DockerfileBuilderCallbackContext, Task>)`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/bd20f904cde09ecb9c9ae5116a6f13614bf2d7c2/src/Aspire.Hosting/ApplicationModel/DockerfileBuilderCallbackAnnotation.cs#L45-L47)

Adds a callback function to be invoked during the Dockerfile build process.

```csharp
public class DockerfileBuilderCallbackAnnotation
{
    public void AddCallback(
        Func<DockerfileBuilderCallbackContext, Task> callback)
    {
        // ...
    }
}
```

## Parameters

- `callback` (`Func<DockerfileBuilderCallbackContext, Task>`)
  The callback function to add.