private static string FormatSingleRule(Rule rule, string forField)
{
var tb = new TagBuilder(rule.RuleName);
tb.MergeAttributes(rule.ListParameters());
tb.MergeAttribute("forfield", forField);
var errorMessage = rule.ErrorMessageOrResourceString;
if(errorMessage != null)
tb.MergeAttribute("errmsg", errorMessage);
return tb.ToString(TagRenderMode.SelfClosing);
}