如何修改此正则表达式，以便它只匹配目录并排除文件？

Question

This is the regex pattern: ^\\D:(\\\\\\w.+(\\\\?))+$

〇 Ideal matches (expected):
C:\\folder1\\folder2
C:\\folder1\\folder2\\

✖ But it also matches (actual):
C:\\folder1\\folder2\\file1.txt
C:\\folder1\\folder2\\file2.docx

Question (so that it matches the OP title):
How should I change this regex so it includes files as mentioned in the above file examples?

OR

Subquestion: Do you have any suggestions as an alternative to using Regex? Please refer below for details.

Detailed scenario:
In my WinForms app, I have a TextBox wherein its value is being loaded from a configuration file. Values can by anything - integers, strings, and even directories. If it looks like a directory (this is why I used regex), I want to validate this value by using System.IO.Directory.Exist() .

Answer 1

My guess is that maybe you are trying to write an expression somewhat similar to:

^\D:(\\\w+\\\w+(\\?))$ 

or maybe not, I'm not so sure.

Test

using System;
using System.Text.RegularExpressions;

public class Example
{
    public static void Main()
    {
        string pattern = @"^\D:(\\\w+\\\w+(\\?))$";
        string input = @"C:\folder1\folder2
C:\folder1\folder2\
C:\folder1\folder2\file1.txt
C:\folder1\folder2\file2.docx

";
        RegexOptions options = RegexOptions.Multiline;

        foreach (Match m in Regex.Matches(input, pattern, options))
        {
            Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index);
        }
    }
}

---

If you wish to explore/simplify/modify the expression, it's been explained on the top right panel of regex101.com . If you'd like, you can also watch in this link , how it would match against some sample inputs.

---

RegEx Circuit

jex.im visualizes regular expressions:

Answer 2

Because file1.txt as well as file2.docx are valid folder names, a better approach would be just to do a simple regex check:

(?i)^[A-Z]:\\

If input string matches this regex we consider that input string is a file system path and then you can try/catch System.IO.Directory.Exist() to actually check if provided path is an existing directory.

Answer 3

Your Regex:

^\\D:(\\\\\\w+(\\\\?))+$

It would take any kind of path without the files.

Example the Result:

Accepted > D:\Folder1\Folder2
Accepted > D:\Folder1\Folder2\
Not Accepted > D:\Folder1\Folder2\text.txt
Accepted > D:\Folder1\Folder2\Folder3
Accepted > D:\Folder1\Folder2\Folder3\

and with more folder is also accepted like the example.

To include the files, just add .* like this:

^\\D:(\\\\\\w+(\\\\?)).* without any specific folder name, this one is not efficient because with only this .* , you also get the same result.

^\\D:(\\\\A\\\\).* with first specific folder name and the whatever folder name and files.

^\\D:\\\\\\w+\\\\\\w+\\\\?\\w+.\\..* with 2 folder is a must then follow by files.

Simulation Here Regex101

Switch regex version to see other pattern or copy paste the regex to test.