CODEWITHSUNDEEP
c#asp.net-mvc
trap
trap

Reputation: 2640

How to inject own services in Controller

I tried to inject my own service in my api controller, but it throws an InvalidOperationException. It is unable to resolve the service. (.NET 5)

What I am doing wrong?

public class MyController : ControllerBase
{
    private readonly MyService _myService;

    public ContractsController(MyService service)
    {
        myService = service;
    }


    [HttpGet("{id}")]
    public Item GetItemById(string id)
    {
        return _myService.getContract(id);
    }
}

This is my Startup file:

public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {

            services.AddControllers();
            services.AddSwaggerGen(c =>
            {
                c.CustomOperationIds(selector => $"{selector.HttpMethod.ToLower().Pascalize()}{selector.ActionDescriptor.RouteValues["controller"]}");
                c.SwaggerDoc("v1", new OpenApiInfo { Title = "My.Portal.Server", Version = "v1" });
            });
            services.AddCors(options =>
            {
                options.AddDefaultPolicy(builder =>
                {
                    builder.SetIsOriginAllowed(origin => new Uri(origin).IsLoopback)
                    .WithOrigins(Configuration.GetSection("AllowedOrigins").Get<string[]>())
                    .AllowAnyHeader()
                    .AllowAnyMethod();
                });
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseSwagger();
                app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "My.Portal.Server v1"));
            }

            app.UseHttpsRedirection();

            app.UseRouting();

            app.UseAuthorization();

            app.UseCors();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }

If i create a new instance in the constructor, then it is working.

thank you in advance!

Upvotes: 1

Views: 693

Answers (1)

Peter Dongan
Peter Dongan

Reputation: 2308

Example, as per request in comment:

        public void ConfigureServices(IServiceCollection services)
        {
             services.AddScoped<IInfoStorageService>(c => new InfoStorageService(Configuration["ImageInfoConnectionString"]));

This is telling the application to pass an instance of InfoStorageService in where IInfoStorageService is injected. It is instantiated with a connection string that it reads from configuration.

AddScoped means that the injected service will be the same across the request. You can also use AddTransient() which means it will not match any other uses of the service, or you can use AddSingleton(), which means it will use the same instance through the whole lifetime of the application.

Upvotes: 3

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