I want to list the contents of a LIST <int> into a textBox or even a Label and cannot figure out how.

Try this:

      using System.Text;

      // ........................

      StringBuilder sb = new StringBuilder();
      for (int i = 0; i < arraylist.Count; i++)
      {
        sb.Append(arraylist[i].ToString());
        if (i < arraylist.Count -1)
          sb.Append ("\r\n");
      }

      textBox1.Multiline = true; 
      textBox1.Text = sb.ToString();