public static bool AddClass(this TagHelperAttributeList attributes, string className)
{
if (string.IsNullOrWhiteSpace(className))
{
throw new ArgumentNullException(nameof(className));
}
if (!attributes.TryGetAttribute("class", out TagHelperAttribute classAttribute))
{
attributes.Add(new TagHelperAttribute("class", className));
return(true);
}
if (attributes.ContainsClass(className))
{
return(false);
}
string classes = classAttribute.Value.ToString();
attributes.SetAttribute("class", string.Join(" ", className, classes));
return(true);
}
