Named groups in C# regex

I like feature for named group captures as I used in post about ispell parsing. Recently I worked on a program in C# and was wondering if this is supported by .net Regex implementation.

It turned out it is:

static Regex syntax = new Regex(@"(?<command>toggle|turn off|turn on) (?<x1>\d+),(?<y1>\d+) through (?<x2>\d+),(?<y2>\d+)");

public search()
{
    // ...
    Match found = syntax.Match(line);
    if (!found.Success)
        throw new Exception($"Invalid format {line}");

    Console.WriteLine(found.Groups["command"].Value);
    // ...
}

As seen above, the format is (?<name>group regex) and .Groups property of the Match allows specify both number (starting from 1 counting opening brace from left) and string with name of the group.

I was also looking for a way to specify case-insensitive regex without the RegexOptions.IgnoreCase option. This is useful if the regex is specified in a configuration and we might want to have insensitive match.

Regex r1 = new(@"hello", RegexOptions.IgnoreCase);
Regex r2 = new(@"(?i)hello");

Both examples used above are equivalent, just the second one marks exact start of the insensitiveness and can be also ended with (?-i).