C＃解析RegexOptions中的正则表达式

Question

I've got a function that compares user-supplied regular expressions to strings and they have the ability to include flags in them, but only in the regular expression string. That string could look something like (?!.*(alpha|beta|chi)).*standard.*/s and needs to take out the /s . I understand that I can pass though multiple RegexOptions with || but is there some object I can create to pass through any of the flags that are found? I don't know if they will be sending in one flag or multiple and it could be any combination.

String flags = "";
if(Regex.IsMatch(regex, "/x*s*m*i*")){
    flags = Regex.Match(regex, "/x*s*m*i*").ToString();
    Regex.Replace(regex, "/x*s*m*i*", "");
}
if (flags.Contains('x')) {
    #add to some array/list of RegexOptions to pass as parameter
} else if (flags.Contains('i')) {
    #add to some array/list of RegexOptions to pass as parameter
} else if ((flags.Contains('s'))) {
    #add to some array/list of RegexOptions to pass as parameter
} else if (flags.Contains('m')) {
    #add to some array/list of RegexOptions to pass as parameter
}
if (Regex.IsMatch(source_box.Text, regex, /*Array/list of any number of RegexOptions*/))
{
    //Match found
}

Answer 1

Your question is quite unclear, so i will only answer to part of it, you seem to misuse regex at all, i advice you to once again review what you want to achieve and read more on regex.

As for part that I'm quite sure: Did you thought about passing parameters of regex not inside regex but, for example, by checkboxes . Of course if placing of parameter is of no matter - I really don't know what you want to achieve. If each parameter can be used at most once then for sure if statement in middle of code which you've posted is not good, to include mixed set of options it should look like this

EDIT (options in particular conditions doesn't correspond to actual regex options associated with these letters, they are random just to serve as example)

            string flags = "/x/i/m";

            RegexOptions regExOpts = RegexOptions.None;

            if (flags.Contains('x')) {
                regExOpts |= RegexOptions.Multiline;
            }

            if (flags.Contains('i')) {
                regExOpts |= RegexOptions.IgnoreCase;
            }

            if (flags.Contains('s')) {
                regExOpts |= RegexOptions.Singleline;
            }

            if (flags.Contains('m')) {
                 regExOpts |= RegexOptions.ExplicitCapture;
            }

            MessageBox.Show(regExOpts.ToString());

EDIT After seeing your comment your problem is more clear, but still there is some stuff that I am not sure. Anyway I've made some changes to code and it is probably what you've been looking for, Its late here I'm in bit of hurry so see the notice above code. Hope it will solve your problems