Great question, and the answer is not a simple one. There is no “show me all .net core versions” command, but there’s hope. EDIT: I’m not sure when it was added, but the info command now includes this information in its output. It will print out the installed runtimes and SDKs, as well as some … Read more
To break down the error message: Unable to resolve service for type ‘WebApplication1.Data.BloggerRepository’ while attempting to activate ‘WebApplication1.Controllers.BlogController’. That is saying that your application is trying to create an instance of BlogController but it doesn’t know how to create an instance of BloggerRepository to pass into the constructor. Now look at your startup: services.AddScoped<IBloggerRepository, BloggerRepository>(); … Read more
For me, the solution (workaround) is to turn off JavaScript debugging on Chrome, which I believe is a new feature introduced in VS 2017. Go to Tools > Options > Debugging > General and turn off the setting for Enable JavaScript Debugging for ASP.NET (Chrome and IE). This is a known issue already, and seems … Read more
See the announcement for ASP.NET Core 3 Preview 4, which explains that this tool is no longer built-in and requires an explicit install: The dotnet ef tool is no longer part of the .NET Core SDK This change allows us to ship dotnet ef as a regular .NET CLI tool that can be installed as … Read more
I did a simple workaround using Func when I found myself in this situation. Firstly declare a shared delegate: public delegate IService ServiceResolver(string key); Then in your Startup.cs, setup the multiple concrete registrations and a manual mapping of those types: services.AddTransient<ServiceA>(); services.AddTransient<ServiceB>(); services.AddTransient<ServiceC>(); services.AddTransient<ServiceResolver>(serviceProvider => key => { switch (key) { case “A”: return serviceProvider.GetService<ServiceA>(); … Read more
The IServiceCollection interface is used for building a dependency injection container. After it’s fully built, it gets composed to an IServiceProvider instance which you can use to resolve services. You can inject an IServiceProvider into any class. The IApplicationBuilder and HttpContext classes can provide the service provider as well, via their ApplicationServices or RequestServices properties … Read more
The approach recommended by the ASP.Net Core team is to use the new policy design which is fully documented here. The basic idea behind the new approach is to use the new [Authorize] attribute to designate a “policy” (e.g. [Authorize( Policy = “YouNeedToBe18ToDoThis”)] where the policy is registered in the application’s Startup.cs to execute some … Read more
TL;DR Transient objects are always different; a new instance is provided to every controller and every service. Scoped objects are the same within a request, but different across different requests. Singleton objects are the same for every object and every request. For more clarification, this example from .NET documentation shows the difference: To demonstrate the … Read more