How to get new line in HTML using C#

See more:

C#

i preparing a Windows form Utility,when i clicked on button it has to generate HTML document same as my Windows form, every thing is fine ,but the problem is when i am giving multi line text input to my text box ,it is giving as Continues Text,can any please help to get new line text in html using c#.

What I have tried:

sb.AppendFormat("{0}
","

"+textBox3.Text+"

");
and i also tried
sb.AppendFormat("{0}
",textBox3.Text+"
");