InputField.multiLine

Description

If the input field supports multiple lines.

using UnityEngine;
using System.Collections;
using UnityEngine.UI; // Required when Using UI elements.

public class Example : MonoBehaviour
{
    public InputField mainInputField;

    public void Update()
    {
        //Check to see if the input field is set to allow multiple lines.
        if (mainInputField.multiLine)
        {
            //Set the input field to only allow Single Lines, if it is currently set to allow Multiple lines.
            mainInputField.lineType = InputField.LineType.SingleLine;
            //Print to console
            Debug.Log("The main input field is now set to allow single lines only!");
        }
    }
}