Managed c++ cross threading

Question

I got a thread:

    static void TestThread(System::Object ^obj)
    {
        Bot ^ob = (Bot^) obj;

            while( ob->Threads[0]->IsAlive ){
    ob->textBox->text = "test"; // Cross threading error...

Thread::Sleep(100);

    }

    }

Dont know what to do i read about InvokeRequired and Invoke but didnt understand it..

Please help