Hi Y'all,

If someone could please help me with the below issues?

I built a Web API using ASP.Net Core (from Microsoft Tutorial). When calling the API, I got this error below:

The error can be read here:

System.InvalidOperationException: Unable to resolve service for type 'TapAPI.Models.TodoContext' while attempting to activate 'TapAPI.Controllers.TapController'. at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired) at lambda_method3(Closure , IServiceProvider , Object[] ) at Microsoft.AspNetCore.Mvc.Controllers.ControllerActivatorProvider.<>c__DisplayClass7_0.b__0(ControllerContext controllerContext) at Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider.<>c__DisplayClass6_0.g__CreateController|0(ControllerContext controllerContext) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync() --- End of stack trace from previous location --- at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|20_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Logged|17_1(ResourceInvoker invoker) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Logged|17_1(ResourceInvoker invoker) at Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger) at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context) at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext) at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider) at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context) HEADERS ======= Accept: text/plain Host: localhost:7292 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.74 Safari/537.36 Edg/99.0.1150.46 :method: GET Accept-Encoding: gzip, deflate, br Accept-Language: en-US,en;q=0.9 Referer: https://localhost:7292/swagger/index.html sec-ch-ua: " Not A;Brand";v="99", "Chromium";v="99", "Microsoft Edge";v="99" DNT: 1 sec-ch-ua-mobile: ?0 sec-ch-ua-platform: "Windows" sec-fetch-site: same-origin sec-fetch-mode: cors sec-fetch-dest: empty

Controller implementation:

TodoContext Implementation:

Could someone please point me out where to look at to address this issue.

Thank you and best regards,

Thank you Bruce! Do you have any documentation on it. My first time working with Angular and ASP.Net so I am a little bit lost. And I am the only developer in the team so I have to turn to Microsoft Community for help. I will also research online on how to register TodoContext with Service at startup.

Really appreciate your help!

Best Regards,

clearly you have not read the docs or done any tutorials. DI injection is key to asp.net development

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/dependency-injection?view=aspnetcore-6.0

builder.Services.AddDbContext<TodoContext>(options =>
    options.UseSqlServer(connectionString));