Helper methods to execute non public Methods or get/set non public properties.

NonPublicMethodsHelper.cs

using System;
using System.Reflection;

namespace com.github.coenm
{
    public static class NonPublicMethodsHelper
    {
        public static MethodInfo GetNonPublicMethod(object instance, string methodName)
        {
            var instanceType = instance.GetType();
            return GetNonPublicMethod(instanceType, methodName);
        }

        public static MethodInfo GetNonPublicMethod(Type instanceType, string methodName)
        {
            return instanceType.GetMethod(methodName, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
        }

        public static PropertyInfo GetNonPublicProperty(Type instanceType, string propertyName)
        {
            return instanceType.GetProperty(propertyName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
        }

        public static void InvokeNonPublicMethod(object instance, string methodName, object[] parameters = null)
        {
            var method = GetNonPublicMethod(instance, methodName);
            method.Invoke(instance, parameters);
        }

        public static T InvokeNonPublicMethod<T>(object instance, string methodName, object[] parameters = null)
        {
            var method = GetNonPublicMethod(instance, methodName);
            var result = (T)method.Invoke(instance, parameters);
            return result;
        }

        public static T GetValueOfNonPublicProperty<T>(object instance, string propertyname)
        {
            var instanceType = instance.GetType();
            var prop = GetNonPublicProperty(instanceType, propertyname);
            var value = (T)prop.GetValue(instance);
            return value;
        }
    }
}