C#•3y ago

Cannot resolve constructor for String type. Using Unity container

I am sending a string to StringCon Class but it doesnt resolve when injecting into HomeController... here is the code

var con = ConfigurationManager.AppSettings["MyConnectionString"];
            var paramStringCon = new ParameterOverrides();
            container.RegisterType<StringCon>();
            container.Resolve<StringCon>(new ResolverOverride[]
            {
                new ParameterOverride("str", con)
            });
            
            var logProd = container.Resolve(typeof(Microsoft.Extensions.Logging.ILogger<ProductoRepository>));

                container.RegisterType<ProductoRepository>(nameof(ProductoRepository),
                new InjectionConstructor(container.Resolve<StringCon>(new ResolverOverride[]
            {
                new ParameterOverride("str", con)
            }), logProd));
             new UnityDependencyResolver(container);
            DependencyResolver.SetResolver(new UnityDependencyResolver(container));

var con = ConfigurationManager.AppSettings["MyConnectionString"];
            var paramStringCon = new ParameterOverrides();
            container.RegisterType<StringCon>();
            container.Resolve<StringCon>(new ResolverOverride[]
            {
                new ParameterOverride("str", con)
            });
            
            var logProd = container.Resolve(typeof(Microsoft.Extensions.Logging.ILogger<ProductoRepository>));

                container.RegisterType<ProductoRepository>(nameof(ProductoRepository),
                new InjectionConstructor(container.Resolve<StringCon>(new ResolverOverride[]
            {
                new ParameterOverride("str", con)
            }), logProd));
             new UnityDependencyResolver(container);
            DependencyResolver.SetResolver(new UnityDependencyResolver(container));

12 Replies

Yawnder•3y ago

Are you just like... writing anything you can think of? Your registrations should happen very early in the process normally, and you should seldom use overrides. Use named registrations instead.

undisputed world champions•3y ago

i'd wrap the string in a options-class, register and configure it in the ServiceCollection and let DI inject it into constructors as needed https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/options?view=aspnetcore-6.0

Options pattern in ASP.NET Core

Discover how to use the options pattern to represent groups of related settings in ASP.NET Core apps.

PontiacGTXOP•3y ago

it is what I have done if you see container.RegisterType<StringCon>();

undisputed world champions•3y ago

sry somehow completely missed it's about unity ^^ but i'm with yawnder ... why are you trying to override the parameter when resolving, instead of registering it with the right value? you seem to use the same value in all places, right?

phaseshift•3y ago

that isn't 'IOptions' type/pattern that was being referenced by icebear

PontiacGTXOP•3y ago

technically yes but no I think that is more of an automatic thing in ASP.NET Core I fixed it had to instance from a factory container.RegisterFactory(typeof(StringCon),instance=>new StringCon(con), FactoryLifetime.Scoped);

phaseshift•3y ago

your string comes from config

PontiacGTXOP•3y ago

yeah i read it from the Config

phaseshift•3y ago

so you can just use IOptions instead of hard wiring all these overridees

PontiacGTXOP•3y ago

ASP.NET has IOptions? it isnt asp.net core

phaseshift•3y ago

i dont think ioptions is new

PontiacGTXOP•3y ago

so yeah I have to manually bind the properties

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Cannot resolve constructor for String type. Using Unity container