A transient lifetime tells the ASP.NET Core dependency-injection container to create a new service instance every time that service is requested. Different parts of one dependency graph can therefore receive different instances of the same type. section 9.4 section 9.4.1
Use transient registration with these practical expectations:
- Register a service with AddTransient<T>() or AddTransient<TService, TImplementation>(). section 9.4.1 section 9.1
- Expect new instances both between HTTP requests and within a single request. section 9.4.1
- Prefer lightweight services with little or no state, because transient registration can create many objects. section 9.4.1
- Resolve transient services from an active scope; create and dispose a scope when resolving them outside an HTTP request. section 9.5 section 9.6
Seeing unique instances
Register both DataContext and Repository as transient. A handler receives DataContext directly while Repository receives its own DataContext dependency. Reading RowCount from both can produce different values in the same request, demonstrating that each request creates a fresh instance. section 9.4.1 section 9.4
builder.Services.AddTransient<DataContext>(); builder.Services.AddTransient<Repository>();
Inspect the minimal AddTransient registration for DataContext and Repository. section 9.4.1
