Extended TextBox to validate IP Address using Dependency Properties

Hi,

I am working on a desktop application. In my application I have a requirement like User is going to enter an IP Address as string in a textbox. Need to validate, such that user is allowed to enter Numeric and '.' only.

ex: 192.158.66.98

For this, I tried to create Extended TextBox by inheriting TextBox class and in the constructor, I taken event

TextChanged += new EventHandler(OnTextChanged);  and implemented OnTextChanged, but I am unable to validate the user input properly.

If anyone has written any masked textBox or any ExtendedTextBox to validate the IP Address , PLease share.

Any suggestion....much appreciated.

Thanks.