Question

I’m building an application that saves named regular expressions into a database. Looks like this:

I’m using Asp.Net forms. How can I validate the entered regex? It would like the user to know if the entered regex is not a valid .Net regular expression.

The field should reject values like:

^Wrong(R[g[x)]]$
Invalid\Q&\A

Answer 1

Make new Regex class out of it. If it throws exception, then it is invalid.

try{
  new Regex(expression)
}
catch(ArgumentException ex)
{
  // invalid regex
}

// valid regex

I know. Using exceptions for code logic is wrong. But this seems to be only solution.