InputField.onValidateInput

Description

The function to call to validate the input characters.

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

public class Example : MonoBehaviour
{
    public InputField mainInputField;

    public void Start()
    {
        // Sets the MyValidate method to invoke after the input field's default input validation invoke (default validation happens every time a character is entered into the text field.)
        mainInputField.onValidateInput += delegate(string input, int charIndex, char addedChar) { return MyValidate(addedChar); };
    }

    private char MyValidate(char charToValidate)
    {
        //Checks if a dollar sign is entered....
        if (charToValidate == '$')
        {
            // ... if it is change it to an empty character.
            charToValidate = '\0';
        }
        return charToValidate;
    }
}