Using DataAnnotations with Regular Expressions to not Match

Question

Is it possible with DataAnnotation s and regular expressions to filter an entry in the text box ? ie To trigger an invalid response when the word "apt" is in the string ?

Answer 1

Yes you can do that using negative look-arounds, like this:

public class MyModel
{
    [RegularExpression(@"^((?!apt).)*$", ErrorMessage = "You can not have that")]
    public string MyValue { get; set; }
}

Here is a good reference question for these types of regular expressions.

Regular expression to match string not containing a word?