# EnvironmentCallbackContext Constructors

- Package: [Aspire.Hosting](/reference/api/csharp/aspire.hosting.md)
- Type: [EnvironmentCallbackContext](/reference/api/csharp/aspire.hosting/environmentcallbackcontext.md)
- Kind: `Constructors`
- Members: `2`

Represents a callback context for environment variables associated with a publisher.

## EnvironmentCallbackContext(DistributedApplicationExecutionContext, Dictionary<string, object>, CancellationToken)

- Name: `Constructor(DistributedApplicationExecutionContext, Dictionary<string, object>, CancellationToken)`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/bd20f904cde09ecb9c9ae5116a6f13614bf2d7c2/src/Aspire.Hosting/ApplicationModel/EnvironmentCallbackContext.cs#L16-L75)

Represents a callback context for environment variables associated with a publisher.

```csharp
public class EnvironmentCallbackContext
{
    public EnvironmentCallbackContext(
        DistributedApplicationExecutionContext executionContext,
        Dictionary<string, object>? environmentVariables = null,
        CancellationToken cancellationToken = default(CancellationToken))
    {
        // ...
    }
}
```

## Parameters

- `executionContext` ([DistributedApplicationExecutionContext](/reference/api/csharp/aspire.hosting/distributedapplicationexecutioncontext.md))
  The execution context for this invocation of the AppHost.
- `environmentVariables` (`Dictionary<string, object>`) `optional`
  The environment variables associated with this execution.
- `cancellationToken` (`CancellationToken`) `optional`
  A [EnvironmentCallbackContext.CancellationToken](/reference/api/csharp/aspire.hosting/environmentcallbackcontext/properties.md#cancellationtoken).

## EnvironmentCallbackContext(DistributedApplicationExecutionContext, IResource, Dictionary<string, object>, CancellationToken)

- Name: `Constructor(DistributedApplicationExecutionContext, IResource, Dictionary<string, object>, CancellationToken)`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/bd20f904cde09ecb9c9ae5116a6f13614bf2d7c2/src/Aspire.Hosting/ApplicationModel/EnvironmentCallbackContext.cs#L28-L31)

Initializes a new instance of the [EnvironmentCallbackContext](/reference/api/csharp/aspire.hosting/environmentcallbackcontext.md) class.

```csharp
public class EnvironmentCallbackContext
{
    public EnvironmentCallbackContext(
        DistributedApplicationExecutionContext executionContext,
        IResource resource,
        Dictionary<string, object>? environmentVariables = null,
        CancellationToken cancellationToken = default(CancellationToken))
    {
        // ...
    }
}
```

## Parameters

- `executionContext` ([DistributedApplicationExecutionContext](/reference/api/csharp/aspire.hosting/distributedapplicationexecutioncontext.md))
  The execution context for this invocation of the AppHost.
- `resource` ([IResource](/reference/api/csharp/aspire.hosting/iresource.md))
  The resource associated with this callback context.
- `environmentVariables` (`Dictionary<string, object>`) `optional`
  The environment variables associated with this execution.
- `cancellationToken` (`CancellationToken`) `optional`
  A [EnvironmentCallbackContext.CancellationToken](/reference/api/csharp/aspire.hosting/environmentcallbackcontext/properties.md#cancellationtoken).