RadDateInput accepts letters. Something i dont want

[Robel]

So i have dynamically added a RadDateInput to my application. So by default if a user put in a number between 1-31 the dateinput-textbox reacts so it takes the current month and current year and then the number that the user have put in and then builds a date string automatically. if it is below 1 or over 31 the textbox will not accept. But if it is between 1-31 it will as i said take current month and year and then with the day number the user put in, it will automatically give me a date. For example if i put in 11 in the textbox the textbox will automatically giva me 2017/03/11. The problem is that if i put in for example 11 plus any letters it still gives me a date string with current year and current month(example: 11mfweieof would give me today 2017/03/10). But i want it to work if you put in any letters to the textbox i want the textbox to not accept it. Is this possible?