iOS text input

When using the iOS keyboard, there is a one-line box for viewing and editing the text. Is there a way to make that box show more than one line of text? Or is there a workaround?

keyboard = iPhoneKeyboard.Open(stringToEdit, iPhoneKeyboardType.Default); //blue keyboard
if (keyboard.text.length > 9){
keyboard.text = keyboard.text.Substring(0, 9);
}

This code gets the keyboard to open and limits the amount of characters you can enter so it may be something to do with that. If not you would have to set a variable to enter a line break which I have used before as
after a certain amount of characters.