MvvmLight Messenger Send Derived Class Type

NotifyHelper.cs

namespace My.Util.Messaging
{
    using System;
    using System.Collections.Concurrent;
    using System.Diagnostics;
    using System.Linq;
    using System.Reflection;

    using GalaSoft.MvvmLight.Messaging;

    /// <summary>
    /// NotifyHelper is a util class for dispatching message
    /// </summary>
    /// <remarks>
    /// Here in this class we simply assume that all of the Types are already loaded in the assembly level.
    /// </remarks>
    public class NotifyHelper
    {
        private static readonly Lazy<MethodInfo> SendGenericMethod =
            new Lazy<MethodInfo>(
                () =>
                    Messenger.Default.GetType()
                        .GetMethods()
                        .FirstOrDefault(x => x.Name == nameof(Messenger.Default.Send) && x.IsGenericMethod));

        private static readonly ConcurrentDictionary<Type, MethodInfo> MethodMap =
            new ConcurrentDictionary<Type, MethodInfo>();

        /// <summary>
        /// Use MvvmLight Messenger to send specific type of message object.
        /// </summary>
        /// <remarks>
        /// This method takes object as parameter and uses reflection to get the specific type and send it.
        /// To boost performance, a ConcurrentDictionary is used for Type->Method mapping.
        /// </remarks>
        /// <param name="msg"></param>
        public static void NotifySpecificType(object msg)
        {
            var type = msg.GetType();
            MethodInfo method;
            if (MethodMap.ContainsKey(type))
            {
                method = MethodMap[type];
            }
            else
            {
                var genericMethod = SendGenericMethod.Value;
                Debug.Assert(genericMethod != null);
                method = genericMethod.MakeGenericMethod(type);
                MethodMap[type] = method;
            }

            method.Invoke(Messenger.Default, new[] { msg });
        }
    }
}