Should I Inject Dependencies into Attributes?

Property Dependency Injection: Not Recommended

Property injection should generally be avoided due to limitations of CLR and frameworks such as MVC and Web API.

Question

In your code, injecting IPermissionService into AuthorizeAttribute via property injection will be problematic because at runtime permissionService will be null.

Solution

Please consider the following:

Option 1: Separate data and behavior

• Extract logic from attributes into a service
• Register the service in the container
• Use attributes to parse and call the service's method

Option 2: Use Humble Objects

• Move all logic in properties into custom services
• Register the service in the container
• Let the property's AuthorizeCore method resolve the service and call its method

Which option to choose?

• Option 1: For design simplicity, multiple properties, or defining properties in an assembly independent of MVC.
• Option 2: In other cases, a more pragmatic approach.

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