Main.cs

using System;
using System.Threading;
using ServiceStack;
using ServiceStack.Text;


var useUtc = JsConfig.AlwaysUseUtc;
TestClass t1 = new TestClass(){A=5, B="Hello"};
t1.TC2 = new TestClass2(){A2="Hello from TestClass2", B2=10};


for(int i=0;i<10;i++)
{
   t1.TC2.B2 += i;
}

packages.config

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="ServiceStack" version="4.0.56" targetFramework="net45" />
  <package id="ServiceStack.Client" version="4.0.56" targetFramework="net45" />
  <package id="ServiceStack.Common" version="4.0.56" targetFramework="net45" />
  <package id="ServiceStack.Interfaces" version="4.0.56" targetFramework="net45" />
  <package id="ServiceStack.OrmLite" version="4.0.56" targetFramework="net45" />
  <package id="ServiceStack.Razor" version="4.0.56" targetFramework="net45" />
  <package id="ServiceStack.Redis" version="4.0.56" targetFramework="net45" />
  <package id="ServiceStack.Server" version="4.0.56" targetFramework="net45" />
  <package id="ServiceStack.Text" version="4.0.56" targetFramework="net45" />
</packages>

TestClass.cs

public class TestClass
{
   public int A { get; set; }
   
   public string B { get; set; }
   
   public TestClass2 TC2 { get; set; }
}

TestClass2.cs

public class TestClass2
{
   public string A2 { get; set; }
   
   public int B2 { get; set; }
}