# ReferenceExpression Fields

- Package: [Aspire.Hosting](/reference/api/csharp/aspire.hosting.md)
- Type: [ReferenceExpression](/reference/api/csharp/aspire.hosting/referenceexpression.md)
- Kind: `Fields`
- Members: `1`

Represents an expression that might be made up of multiple resource properties. For example, a connection string might be made up of a host, port, and password from different endpoints.

## Empty

- Name: `Empty`
- Modifiers: `static` `readonly`
- Returns: [ReferenceExpression](/reference/api/csharp/aspire.hosting/referenceexpression.md)
- Source: [GitHub](https://github.com/microsoft/aspire/blob/bd20f904cde09ecb9c9ae5116a6f13614bf2d7c2/src/Aspire.Hosting/ApplicationModel/ReferenceExpression.cs)

Represents an empty reference expression with no name, value providers, or arguments.

```csharp
public static readonly ReferenceExpression Empty
```

## Remarks

Use this field to represent a default or uninitialized reference expression. The instance has an empty name and contains no value providers or arguments.