Thread: accessing windows forms textbox properties

i have a class that outputs text to the console, i want to output the same text to a textbox, however the console method is in a different class, i have been raeding Deitel C# how to program and see various ways to achieve this but im not sure which way is best. here are the classes involved in outputing the text

Code:

using System;
using System.Collections;

namespace TrafficControlSim
{
public class TrafficQueue
	{
	private Queue vehicleQueue;//fifo object
    
	// constructor - one integer input  
	public TrafficQueue(int maximumQueueSize)
		{
		vehicleQueue = new Queue(maximumQueueSize);
		}

	public void Arrive(Vehicle arrival)
		{
		vehicleQueue.Enqueue(arrival);//add vehicle to queue
		}

	public int TrafficQueueSize()
		{
		return vehicleQueue.Count;
		}

	
	public Vehicle Depart()
	{
		Vehicle aVehicle;
		if (vehicleQueue.Count>0)
		{	
			aVehicle=(Vehicle)vehicleQueue.Dequeue();
			vehicleQueue.TrimToSize();
			return (aVehicle);
		}
		else
			return null;
	}

	public int TrafficInQueue()
		{
		if (vehicleQueue.Count>0)
			foreach(Vehicle aVehicle in vehicleQueue)
				aVehicle.ShowType();/* i want to send this text to the textbox in Form1 class */

		else
			
			Console.WriteLine("Traffic Queue is Empty.");
		return vehicleQueue.Count;
		}
	}
}

Code:

using System;

namespace TrafficControlSim
{
	public class Vehicle
	{
		private string registrationNumber;
		private string vehicleType;

		public Vehicle()
		{
			registrationNumber="TBD";
			vehicleType="TBC"; 
		}
		public virtual void ShowDetails()
		{
			Console.WriteLine("Vehicle is a "+vehicleType);
			Console.WriteLine("Registration number is "+registrationNumber);
		}

		public void SetRegistrationNumber(string number)
		{
			registrationNumber=number;
		}
		public void SetVehicleType(string type)
		{
			vehicleType=type;
		}
		public string GetRegistrationNumber()
		{
			return registrationNumber;
		}
		public string GetVehicleType()
		{
			return vehicleType;
		}
		public string ShowType()
		{
			return vehicleType+" ";
		}

	}/* end class */

}/* end namespace */

the Form1 class is rather large which inherits from System.Windows.Forms.Form this class has the textboxs i want to display . I have been working on this for a few days now and am getting quite frustrated due to my lack on knowledge around OOP

thanks in advance