TypeExtensions.cs

using System;
using System.Linq;

namespace Cuemon.Extensions.DependencyInjection
{
    /// <summary>
    /// Extension methods for the <see cref="Type"/> class.
    /// </summary>
    public static class TypeExtensions
    {
        /// <summary>
        /// Returns a value that indicates whether the specified <paramref name="type"/> contains an <see cref="IDependencyInjectionMarker{TMarker}"/> interface.
        /// </summary>
        /// <param name="type">The <see cref="Type"/> to extend.</param>
        /// <param name="result">When this method returns, contains the <see cref="Type"/> of the generic parameter <c>TMarker</c> of <see cref="IDependencyInjectionMarker{TMarker}"/>; otherwise <c>null</c> if the specified <paramref name="type"/> does not have an implemenation of the <see cref="IDependencyInjectionMarker{TMarker}"/> interface.</param>
        /// <returns><c>true</c> if the specified <paramref name="type"/> contains an <see cref="IDependencyInjectionMarker{TMarker}"/> interface, <c>false</c> otherwise.</returns>
        public static bool TryGetDependencyInjectionMarker(this Type type, out Type result)
        {
            Validator.ThrowIfNull(type);
            var dim = type.GetInterfaces().SingleOrDefault(t => t.IsGenericType && t.GetGenericTypeDefinition() == typeof(IDependencyInjectionMarker<>));
            if (dim != null)
            {
                result = dim.GenericTypeArguments.First();
                return true;
            }
            result = null;
            return false;
        }
    }
}