Azure Functions 依赖注入 - 注册自定义服务

Question

I'm trying to do DI in Azure Functions V2 with my service but even after reading the documentation I'm not understanding how to register a service with parameters.

In the example below I want to use the built-in Logger and the DB context within CustomService and the CustomService within SpecialService . These are in the constructors of the respective services, ie CustomService(IMyContext context, ILogger logger) and SpecialService(ICustomService customService) .

Startup.cs:

[assembly: FunctionsStartup(typeof(Startup))]
namespace AzFunction.IoC
{
    class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            builder.Services.AddLogging();

            var connectionString = "test-conn-string";
            var optionsBuilder = new DbContextOptionsBuilder<MyDbContext>();
            builder.Services.AddDbContext<MyDbContext>(
                options => options.UseSqlServer(connectionString));

            builder.Services.AddScoped<ICustomService, CustomService>();

            builder.Services.AddScoped<ISpecialSerivce, SpecialService>();
        }
    }
}

It compiles and and hits the breakpoints with in startup.cs but does not seem to be able to find the services that are registered.

The error:

Microsoft.Azure.WebJobs.Host: Cannot bind parameter 'customService' to type ICustomService. Make sure the parameter Type is supported by the binding.

Answer 1

I was trying to inject into the Azure functions parameters instead of the constructor, here is the correct way:

public class GreatClass
    {
        private ICustomService _customService;

        public GreatClass(ICustomService customService)
        {
            _customService = customService;
        }

        [FunctionName("MyFunc")]
        public async Task Run([TimerTrigger("%RunFrequency%", RunOnStartup = true)]TimerInfo myTimer,
            // ICustomService customService, // Incorrect!
            ILogger log)
        {
            //Logic
        }
    }