using System;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(typeof(outer.Test<>).GetTypeName());

        Console.WriteLine(typeof(outer.Test<other.inner>).GetTypeName());

        Console.WriteLine(typeof(outer.Test<>).GetTypeName());

    }

    class outer

    {

      public class Test<T>

      {

      }

    }

    class other

    { public class inner

        {

    }

    }

}

    public static class TypeEx

    {

        public static string GetTypeName(this Type type)

        {

            if (type == null)

                throw new ArgumentNullException(nameof(type));

​

            if (!type.IsGenericType)

                return type.GetNestedTypeName();

​

            StringBuilder stringBuilder = new StringBuilder();

            _buildClassNameRecursiv(type, stringBuilder);

            return stringBuilder.ToString();

        }

​

        private static void _buildClassNameRecursiv(Type type, StringBuilder classNameBuilder, int genericParameterIndex = 0)

        {

            if (type.IsGenericParameter)

                classNameBuilder.AppendFormat("T{0}", genericParameterIndex + 1);

            else if (type.IsGenericType)

            {

                classNameBuilder.Append(GetNestedTypeName(type) + "[");

                int subIndex = 0;

                foreach (Type genericTypeArgument in type.GetGenericArguments())

                {

                    if (subIndex > 0)

                        classNameBuilder.Append(":");

​

                    _buildClassNameRecursiv(genericTypeArgument, classNameBuilder, subIndex++);

                }

                classNameBuilder.Append("]");

            }

            else

                classNameBuilder.Append(type.GetNestedTypeName());

        }

        public static string GetNestedTypeName(this Type type)

        {

            if (type == null)

                throw new ArgumentNullException(nameof(type));

            if (!type.IsNested)

                return type.Name;

            StringBuilder nestedName = new StringBuilder();

            while(type != null)

            {

                if(nestedName.Length>0)

                    nestedName.Insert(0,'.');

                nestedName.Insert(0, _getTypeName(type));

                type = type.DeclaringType;

            }

            return nestedName.ToString();

        }

        private static string _getTypeName(Type type)

        {

            return type.IsGenericType ? type.Name.Split('`')[0]: type.Name;

        }

    }

​