C#

Assembly assembly = Assembly.LoadFile(@"pathtofile\TestFile.dll");
var type = assembly.GetType("TestFile.MyType");
if (type == null) return;
object instance = Activator.CreateInstance(type);
PropertyInfo propertyInfo = type.GetProperty("MyHashTable",
                                             BindingFlags.GetProperty | BindingFlags.NonPublic |
                                             BindingFlags.Public | BindingFlags.Instance);
if (propertyInfo != null)
{
    object myHashTable = propertyInfo.GetValue(instance, null);
    Hashtable ht = (Hashtable) myHashTable;
    ht.Add("Hello", "Hello");
}

using System;
using System.Collections.Generic;

namespace TestClassLibrary
{
    public class TYPE
    {
        private static Dictionary<String, String> _PROPERTY = new Dictionary<String, String> { { "first", "First String" },
                                                                                               { "second", "Second String" } };
        public static Dictionary<String,String> PROPERTY { get { return _PROPERTY; } set { _PROPERTY = value; } }
    }
}

using System;
using System.Collections.Generic;
using System.Reflection;

namespace TestReflection
{
    class Program
    {
        static void Main(string[] args)
        {
            Assembly assembly = Assembly.LoadFile(@"D:\Development\Console\Playgroung\TestReflection\TestClassLibrary\bin\Debug\TestClassLibrary.dll");
            Type type = assembly.GetType("TestClassLibrary.TYPE");
            PropertyInfo propertyInfo = type.GetProperty("PROPERTY", BindingFlags.GetProperty | BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static);
            Dictionary<String, String> dictionary = (Dictionary<String, String>)propertyInfo.GetValue(null, null);

            foreach (KeyValuePair<String, String> kv in dictionary)
            {
                Console.WriteLine("{0} => {1}", kv.Key, kv.Value);
            }
        }
    }
}

"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:\\test.xlsx;Extended Properties=\"Excel 12.0;HDR=NO\"";