asp.net core add singelton with database in ctor code example

Example: register all services microsoft .net core dependency injection container

service.RegisterAssemblyPublicNonGenericClasses(… your assembly ref goes here …)
.Where(x => x.Name.EndsWith(“Service”))  //optional
.IgnoreThisInterface<IMyInterface>()     //optional
.AsPublicImplementedInterfaces(ServiceLifetime.Scoped);