# ConnectionStringBuilderExtensions

- Kind: `class`
- Package: [Aspire.Hosting](/reference/api/csharp/aspire.hosting.md)
- Version: `13.4.0`
- Namespace: `Aspire.Hosting`
- Target framework: `net8.0`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/a3766e994fd2cba86c8ac60b8a80268cab7e6383/src/Aspire.Hosting/ConnectionStringBuilderExtensions.cs)

Provides extension methods for adding connection string resources to an application.

## Definition

```csharp
namespace Aspire.Hosting;

public static class ConnectionStringBuilderExtensions
{
    // ...
}
```

## Methods

- [AddConnectionString(IDistributedApplicationBuilder, string, ReferenceExpression)](/reference/api/csharp/aspire.hosting/connectionstringbuilderextensions/methods.md#addconnectionstring-idistributedapplicationbuilder-string-referenceexpression) : `IResourceBuilder<ConnectionStringResource>` `extension` `ats ignored` -- Adds a connection string resource to the distributed application with the specified expression.
- [AddConnectionString(IDistributedApplicationBuilder, string, Action<ReferenceExpressionBuilder>)](/reference/api/csharp/aspire.hosting/connectionstringbuilderextensions/methods.md#addconnectionstring-idistributedapplicationbuilder-string-action-referenceexpressionbuilder) : `IResourceBuilder<ConnectionStringResource>` `extension` `ats ignored` -- Adds a connection string resource to the distributed application with the specified expression.