您可能想使用 Regex.Replace 的重载，该重载接受计算替代的委托:

You probably want to use the overload of Regex.Replace, that accepts a delegate that computes the replacement:

private string GetCodeForTex(Match match)
{
    string tex = match.Groups[1].Value;
    return string.Format(
        "<img src=\"{0}\" alt=\"{1}\" />", GetEscapedUrlForTex(tex), tex);
}

…

Regex.Replace(textWithDollars, @"\$([^\$]*)\$", GetCodeForTex);

您在 GetCodeForTex 中的代码可能有所不同(您可能会想到一个更好的名称)，但是我敢肯定您的想法.

Your code in GetCodeForTex might be different (and you might think of a better name for it), but I'm sure you get the idea.

此外，请谨慎使用此类正则表达式进行简单解析.这意味着除了封装TeX之外，您永远不能将 $ 用作其他用途.如果在输入文本中的某个地方未闭合 $ ，结果将很混乱.

Also, be careful with simple parsing using regexes like this. It means you can never use $ for anything else than enclosing TeX. And the result will be mess if you have unclosed $ somewhere in the input text.