Regex to Validate a filename

David Smith

How to validate if the string has a filename along with the path review below.

I am looking for a regex that validates if the string has a filename along with the path. review below.

Example:

C:\temp\ Incorrect because of ";" Incorrect

C:\temp\example.txt Correct

3 Replies

Know the answer? Post it — somebody with the same question will find it here.

Hemant Srivastava13y ago
Accepted answer
Try this:

^(?:[a-zA-Z]\:|\\\\[\w\.]+\\[\w.$]+)\$?:[\w]+\$*\w([\w.])+$
David Smith13y ago

I am using this in the order below in code, It seems the first regex works for both the filename and the filepath. I never make to the seconds regex if set the string to the data below. review

Example

string filepath = "C:\temp\"

string filename = "C:\temp\"

private const string regex1 = @"^(?:[A-Za-z]\:|\\)(\\[a-zA-Z_\-\s0-9\.]+)+(\.\w+)?$";

      private const string regex2 = @"^(?:[a-zA-Z]\:|\\\\[\w\.]+\\[\w.$]+)\$?:[\w]+\$*\w([\w.])+$";

Regex r= new Regex(regex1 );
             if (!r.IsMatch(filename))
              {
                  throw new ArgumentNullException("filepath");
             }

Regex r= new Regex(regex2);
             if (!r.IsMatch(filename))
              {
                  throw new ArgumentNullException("filename");
             }
Hemant Srivastava13y ago
The above one will work for the following paths like...

\\test\test$\TEST.xls
\\server\share\folder\myfile.txt
\\server\share\myfile.txt
\\123.123.123.123\share\folder\myfile.txt
c:\folder\myfile.txt
c:\folder\myfileWithoutExtension