private void Button1_Click(object sender, EventArgs e)
{
	const string filePath = @"C:\Users\userName\Desktop\numbers.txt";
	const int    maxValue = 10;

	int valueOfNumbers = 0;

	try
	{
		using (StreamReader streamReader = new StreamReader(
					filePath, System.Text.Encoding.Default))
			{
				string  line = " ";
				int     number = 0;

				while (null != (line = streamReader.ReadLine()))
				{
					number = 0;

                    Int32.TryParse(line, out number);

                    if (maxValue > number)
                    {
                        ++valueOfNumbers;
                    }
                }
            }
    }
    catch (Exception ex)
    {
        textBox1.Text = ex.Message;
    }

    textBox1.Text = valueOfNumbers.ToString();
}