namespace tmp {
      public class myClass
        {
            public class InnerClass
            {
                public int I { get; set; }
                public int B { get; set; }
            }
            public string Prop1 { get; set; }
            public Test Prop2 { get; set; }
        }
    }
}

Type type = Type.GetType("tmp.myClass");
            object objInstance = Activator.CreateInstance(type);
            PropertyInfo[] properties = type.GetProperties();
            myClass obj = Activator.CreateInstance(type);

properties[0].SetValue(obj,"MyString");

Type type1 = Type.GetType("tmp.myClass");
        Type type2 = Type.GetType("tmp.myClass.InnerClass");
        var obj = Activator.CreateInstance(type1);
        var obj2 = Activator.CreateInstance(type2);

        PropertyInfo[] properties = type1.GetProperties();
        properties[1].SetValue(obj, obj2);