Transient
CustomService1 — a new instance on every resolution.
When to use: lightweight, stateless services.
Each injection gets its own instance, even within the same request.
Where do the three IDs come from?
When this page loads, ASP.NET Core builds the page model by calling its constructor.
The container resolves ICustomService twice in the page, and also injects
SampleService. Because this service is transient, SampleService receives a new instance — different from both injections in the page.
Page constructor — TransientModel
public TransientModel( ICustomService firstInjection, // parameter 1: first injection ICustomService secondInjection, // parameter 2: second injection SampleService sampleService) // parameter 3: via SampleService { FirstInjectionId = firstInjection.InstanceId; SecondInjectionId = secondInjection.InstanceId; SampleServiceId = sampleService.CustomService.InstanceId; }
SampleService constructor
public SampleService( ICustomService customService, ...) { CustomService = customService; } // This page reads: sampleService.CustomService.InstanceId
Result in this request
| Resolution | Constructor parameter | Instance ID |
|---|---|---|
| First injection | firstInjection |
c4091015-da21-45ba-87d2-d161b1d3163b |
| Second injection | secondInjection |
8768e534-47b5-4a53-bdf7-994baabebd93 |
Via SampleService |
sampleService.CustomService |
ed5e2b78-aeff-4f46-8e37-1e1e45273fc6 |
Every resolution has a unique ID — exactly as shown in the diagram for
GetTransientID (Sample Service and ITransientService differ).
Registration in Program.cs:
builder.Services.AddTransient<ICustomService, CustomService1>();