Create a Textbox on your form (assuming you are using Windows Forms), then use this code:
textBox1.Multiline = true;
textBox1.Dock = DockStyle.Fill;
textBox1.Text = "\r\nHello\r\n\r\n\tHow are you?";
In Windows, a new line is represented by "\r\n" rather than just "\n". If you have a file that contains "\n" characters, you can use a regular expression or String.Replace to fix the characters for display:
textBox1.Text = "\nHello\n\n\tHow are you?".Replace("\n", "\r\n");
Or:
textBox1.Text = System.Text.RegularExpressions.Regex.Replace("\nHello\n\n\tHow are you?", "(?<!\r)\n", "\r\n");
EDIT: Removed some testing code I forgot in there.