# ConnectionStringResource Properties

- Package: [Aspire.Hosting](/reference/api/csharp/aspire.hosting.md)
- Type: [ConnectionStringResource](/reference/api/csharp/aspire.hosting/connectionstringresource.md)
- Kind: `Properties`
- Members: `1`

Adds a connection string to the distributed application a resource with the specified expression.

## ConnectionStringExpression

- Name: `ConnectionStringExpression`
- Modifiers: `get`
- Returns: [ReferenceExpression](/reference/api/csharp/aspire.hosting/referenceexpression.md)
- Source: [GitHub](https://github.com/microsoft/aspire/blob/a3766e994fd2cba86c8ac60b8a80268cab7e6383/src/Aspire.Hosting/ConnectionStringResource.cs#L18)

Describes the connection string format string used for this resource.

```csharp
public ReferenceExpression ConnectionStringExpression { get; }
```