I generated a C#-Client with nswag studio. Now I'm calling a function of this client, that sets the tasks of a customer to done, if the customer is deleted.
If I call this function I will always run into this error message:
InvalidOperationException: Unable to resolve service for type 'R4.Services.TaskService' while attempting to activate 'R4.Services.CustomerService'.
I've already looked for ways to solve it and I know the error's reason, but I don't know how I can solve it. No post or page has helped me to solve it.
This is my code:
The configure-function to register the class in the DI-Container:
public static void Configure(IServiceCollection services, IConfiguration configuration)
{
services.AddScoped<IBaseService<Task>, TaskService>();
services.AddScoped<IBaseService<Customer>, CustomerService>();
}
This is the Customer-Service class:
public class CustomerService: BaseService<Customer>
{
private readonly TaskService _taskService;
public CustomerService(TaskService taskService){
_taskService = taskService;
}
}
If you look at this line
public CustomerService(TaskService taskService)
Then CustomerService
wants to use the service of type TaskService
if we then look at your configure method we see:
services.AddScoped<IBaseService<Task>, TaskService>();
The documentation states that this is
AddScoped<TService, TImplementation>(IServiceCollection)
So you see that the first definition is the TService
which you have defined as IBaseService<Task>
.
But, in your configure method you don't have any definitions of the type TaskService
which your class is expecting. You have instead IBaseService<Task>
. And in your class you have instead defined that the class should receive the Implementation (TaskService).
So then you have several options:
Change your class to be
public CustomerService(IBaseService<Task> taskService)
{
_taskService = taskService as TaskService;
}
or maybe a better approach might be:
Create a new Service
public class ITaskService: IBaseService<Task> {} ....
then change TaskService to implement ITaskService
public class TaskService: ITaskService ....
then define in your configure method
services.AddScoped<ITaskService, TaskService>();
and your class definition to use ITaskService
private readonly ITaskService _taskService;
public CustomerService(ITaskService taskService){
_taskService = taskService;
}
That way, you could also have more services which inherit from IBaseService in the future, if needed.