OptionsPatternSamples - OptionBuilderExtensions

OptionBuilderExtensions.cs

using Microsoft.Extensions.Options;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;

namespace OptionsPatternSamples.Extensions
{
    public static class OptionBuilderExtensions
    {
        public static OptionsBuilder<TOptions> ValidateDataAnnotations<TOptions>(this OptionsBuilder<TOptions> builder) where TOptions : class
        {
            return builder.PostConfigure(options =>
            {
                var validationResults = new List<ValidationResult>();
                var validationContext = new ValidationContext(options);
                var isValid = Validator.TryValidateObject(options, validationContext, validationResults);
                if (isValid) return;

                var message = string.Join("\n - ", validationResults.Select(v => v.ErrorMessage));
                throw new Exception($"{options.GetType()} is invalid:\n - {message}");
            });
        }
    }
}