How can I make this call to log my exceptions recursive?

Question

I have the following code:

protected string formatException(Exception e)
{
    var exError = "<form>";
        if (e == null)
        {
            throw new ArgumentNullException("e");
        }
        exError += "<fieldset><legend><a href='#'>" +
                  "<span class='show-expanded'>collapse message</span>" +
                  "<span class='show-collapsed'>expand message</span>" +
                  "</a></legend><p>" + e.Message + "</p></fieldset>";
        exError += "<fieldset><legend><a href='#'>" +
                  "<span class='show-expanded'>collapse trace</span>" +
                  "<span class='show-collapsed'>expand trace</span>" +
                  "</a></legend><p>" + e.StackTrace + "</p></fieldset>";

        if (e.InnerException != null)
        {
            // same functionality but for the inner exception and the InnerException.InnerException
        }
    return exError + "</form>";
}

When called it formats the exception message. However I would like to make it include the InnerException and the InnerException.InnerException

Is there some way I could do this recursively or would it be better to put the message format in another function and call that?

Answer 1

Here's what I'd do:

protected string formatException(Exception e)
{
    Func<string, string> createFieldSet =
        t =>
            "<fieldset><legend><a href='#'>" +
            "<span class='show-expanded'>collapse message</span>" +
            "<span class='show-collapsed'>expand message</span>" +
            "</a></legend><p>" + t + "</p></fieldset>";

    var exError = new StringBuilder("<form>");
    if (e == null)
    {
        throw new ArgumentNullException("e");
    }
    while (e != null)
    {
        exError.AppendLine(createFieldSet(e.Message));
        exError.AppendLine(createFieldSet(e.StackTrace));
        e = e.InnerException;
    }
    exError.AppendLine("</form>");
    return exError.ToString();
}