ServiceCollectionGenerators

OptionsAttribute

Another common practice while developing .NET applications is to create binding classes. This allows you to configure object properties' values in appsettings.json, create and add an object to the dependency injection container as a IOptions<T>.

namespace My.Namespace;

[Options]
public class DatabaseContextOptions
{
    [Required] public string ConnectionString { get; set; }
}

This will generate the following code:

namespace My.Namespace.Extensions
{
    public static partial class ServiceCollectionExtensions
    {
        internal static IServiceCollection RegisterOptions(this IServiceCollection services) => services.RegisterOptionsForMyNamespace();
        
        public static IServiceCollection RegisterOptionsForMyNamespace(this IServiceCollection services)
        {
            services.AddOptions<My.Namespace.DatabaseContextOptions>().Bind(configuration.GetSection("DatabaseContextOptions")).ValidateDataAnnotations();
            return services;
        }
    }
}

The generated code will make use of the .ValidateDataAnnotations() method. If needed, you can change this behaviour by set the attribute property ValidateDataAnnotations to false.

The attribute also allows you to change the Configuration Section name that will be used to bind the Options from the IConfiguration object.