/// <summary>
/// 创建选择器
/// </summary>
/// <param name="expression">选择器表达式</param>
/// <returns>选择器实例</returns>
public static ICssSelector Create(string expression)
{
if (selectorCache.ContainsKey(expression))
{
return(selectorCache[expression]);
}
var match = casecadingSelectorRegex.Match(expression);
if (!match.Success)
{
throw new FormatException();
}
ICssSelector selector = CssElementSelector.Create(match.Groups["leftSelector"].Value);
foreach (var extraCapture in match.Groups["extra"].Captures.Cast <Capture>())
{
var relative = extraCapture.FindCaptures(match.Groups["relative"]).Single().Value.Trim();
var rightSelector = extraCapture.FindCaptures(match.Groups["rightSelector"]).Single().Value.Trim();
selector = new CssCasecadingSelector(selector, relative, CssElementSelector.Create(rightSelector));
}
lock ( _cacheSync )
{
selectorCache[expression] = selector;
}
return(selector);
}
/// <summary>
/// 获取符合条件的子元素
/// </summary>
/// <param name="container">要获取子元素的容器</param>
/// <param name="selector">用来筛选子元素的元素选择器</param>
/// <returns>符合条件的子元素</returns>
public static IEnumerable <IHtmlElement> Elements(this IHtmlContainer container, string selector)
{
if (container == null)
{
throw new ArgumentNullException("container");
}
if (selector == null)
{
throw new ArgumentNullException("selector");
}
return(CssElementSelector.Create(selector).Filter(Elements(container)));
}
/// <summary>
/// 获取符合条件的兄弟（同级）元素节点
/// </summary>
/// <param name="node">要获取兄弟（同级）元素节点的节点</param>
/// <param name="selector">用于筛选元素的元素选择器</param>
/// <returns>所有的兄弟（同级）元素节点</returns>
public static IEnumerable <IHtmlElement> Siblings(this IHtmlNode node, string selector)
{
return(CssElementSelector.Create(selector).Filter(node.Siblings()));
}
/// <summary>
/// 获取符合条件的父代元素
/// </summary>
/// <param name="node">要获取父代元素集合的节点</param>
/// <param name="selector">用来筛选父代元素的元素选择器</param>
/// <returns>节点的所有父代元素集合</returns>
public static IEnumerable <IHtmlElement> Ancestors(this IHtmlNode node, string selector)
{
return(CssElementSelector.Create(selector).Filter(Ancestors(node)));
}