I am trying to write a Regex to match a valid Hex string but without all zero values.
How to write a Regex to match valid hex string is a common knowledge.
The simplest is ^0[xX][0-9a-fA-F]+$.
But, among all the possible hex strings, the ones match Zero should be invalid.
e.g.,
0x0, 0x00, 0x00000 are all invalid
but
0x01, 0x001, 0x010 are valid
You may use a lookahead to restrict the match:
^0[xX](?!0+$)[0-9a-fA-F]+$
^^^^^^^
Here, after matching 0x or 0X, the (?!0+) negative lookahead fails the match if there are 1+ zeros to the end of the string immediately to the right.
See the regex demo
C# possible usage example:
if (Regex.IsMatch(s, @"^0x(?!0+$)[0-9a-f]+$", RegexOptions.IgnoreCase))
{
// Valid
}