COM export method from object in .exe application

Question

I want to export method from object located in running application using COM, but every tutorial i could find operates methods in .dll files.

Example:

I have a form and I want to access TextBox from another application:

public partial class Form1 : Form
{
  public Form1()
  {
     InitializeComponent();
  }

  public int GetData()
  {
     return Convert.ToInt32(textBox1.Text);
  }
}

How can I export GetData() method so it can be called from another application? Is it possible to make it using COM?

UPD: that question still doesn't explain how to access an existing OBJECT through COM, not CLASS.