<p>I need to validate a certain property to one of my classes. When I set the property, the class should validate the input and if incorrect, set the object to an invalid state.</p>
<p>Question : The property value must be in a certain mask/format eg. &amp;&amp;&amp;&amp;-&amp;&amp;&amp;&amp;-&amp;&amp;&amp;&amp;. I cannot use regular expressions. Is it possible to validate text against a mask value?</p>

Is it possible to validate text
  against a mask value ?
Of course it's possible, in that you could write a function to take a string and a mask and check one against another.
So I'm unclear on what you're asking - are you asking if there are functions in the standard .Net libraries to do this? Or asking for an implementation of a mask-validation function? Or something else?
If you're looking for something in the library to help,
MaskedTextProvider
would probably do it, although it's overkill.