A C# Windows Forms Number Guessing Game

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

        private void btnGo_Click(object sender, EventArgs e)
        {
            Random rnd = new Random();
            int randomNumber = rnd.Next(1, 10);
            int theirNumber = Convert.ToInt32(txtGuess.Text);
            string outcome = "";

            if (randomNumber == theirNumber)
            {
                outcome = "Congratulations! \n You guessed correctly. \n I also thought of: " + randomNumber;
            }
            else if (randomNumber > theirNumber)
            {
                outcome = "Your guess is too low. \n I thought of: " + randomNumber;
            }
            else
            {
                outcome = "Your guess is too high. \n I thought of: " + randomNumber;
            }
            lblResult.Text = outcome;
            txtGuess.Text = "";
            txtGuess.Focus();
        }
    }
}