Principal.cs

using System;
using System.Drawing;
using System.Drawing.Printing;
using System.Windows.Forms;

namespace R814ImprimirDocumento
{
    public partial class Principal : Form
    {
        public Principal()
        {
            InitializeComponent();
        }

        private void btnImprimirDocumento_Click(object sender, EventArgs e)
        {
            PrintDocument documento = new PrintDocument();
            documento.PrintPage += this.Documento_PringPage;

            PrintDialog dialogoImpresion = new PrintDialog();
            dialogoImpresion.Document = documento;

            if (dialogoImpresion.ShowDialog() == DialogResult.OK)
            {
                documento.Print();
            }
        }

        private void Documento_PringPage(object sender, PrintPageEventArgs e)
        {
            using (Font fuente = new Font("Trebuchet", 30))
            {
                float x = e.MarginBounds.Left;
                float y = e.MarginBounds.Top;

                float altoLinea = fuente.GetHeight(e.Graphics);

                for (int i = 0; i < 5; i++)
                {
                    e.Graphics.DrawString("Línea de texto no. " + i.ToString(), fuente, Brushes.Black, x, y);

                    y += altoLinea;
                }
            }
        }
    }
}