# ReferenceExpressionBuilder.appendValueProvider

- Module: [Aspire.Hosting](/reference/api/typescript/aspire.hosting.md)
- Defined on: [ReferenceExpressionBuilder](/reference/api/typescript/aspire.hosting/referenceexpressionbuilder.md)
- Version: `13.4.0`
- Kind: `method`

Appends a value provider to the reference expression

## Definition

```typescript
interface ReferenceExpressionBuilder {
  // ... omitted for brevity
  appendValueProvider(
      valueProvider: any,
      format?: string): void;
}
```

## Signature

```typescript
appendValueProvider(
    valueProvider: any,
    format?: string): void
```

## Parameters

- `valueProvider` (`any`)
- `format` (`string`) `optional`

## Defined on

- [ReferenceExpressionBuilder](/reference/api/typescript/aspire.hosting/referenceexpressionbuilder.md) -- `handle`