/// <summary>
/// 渲染元素和其子节点
/// </summary>
/// <param name="element">要渲染的元素</param>
/// <param name="context">渲染上下文</param>
private static void RenderElementAndChilds(IHtmlElement element, IHtmlRenderContext context)
{
var writer = context.Writer;
var specification = element.Document.HtmlSpecification;
if (specification.IsForbiddenEndTag(element.Name))
{
var builder = new StringBuilder();
builder.Append(GenerateTagHtml(element, true));
if (element.Nodes().Any())
{
throw new FormatException(string.Format(CultureInfo.InvariantCulture, "HTML元素 {0} 不能有任何内容", element.Name));
}
writer.Write(builder);
}
else
{
writer.Write(GenerateTagHtml(element, false));
RenderChilds(element, context);
writer.Write("</{0}>", element.Name);
}
}
/// <summary>
/// 添加元素的副本
/// </summary>
/// <param name="container">要添加副本的容器</param>
/// <param name="index">要添加的位置</param>
/// <param name="element">要创作副本的元素</param>
/// <returns>添加后的元素</returns>
public static IHtmlElement AddCopy(this IHtmlContainer container, int index, IHtmlElement element)
{
if (container == null)
{
throw new ArgumentNullException("container");
}
if (element == null)
{
throw new ArgumentNullException("element");
}
var _element = container.AddElement(index, element.Name);
foreach (var attribute in element.Attributes())
{
_element.AddAttribute(attribute.Name, attribute.AttributeValue);
}
foreach (var node in element.Nodes())
{
AddCopy(_element, node);
}
return(_element);
}
private static void CopyChildNodes(IHtmlElement element, IFreeElement freeElement)
{
foreach (var node in element.Nodes().Reverse())
{
var freeNode = freeElement.Factory.MakeCopy(node);
freeNode.Into(freeElement, 0);
}
}
/*
* /// <summary>
* /// 设置元素的InnerHTML
* /// </summary>
* /// <param name="element">要设置InnerHTML的元素</param>
* /// <param name="html">要设置的HTML文本</param>
* /// <exception cref="System.InvalidOperationException">如果元素不能被安全的修改内容</exception>
* public static void InnerHtml( this IHtmlElement element, string html )
* {
*
* if ( element == null )
* throw new ArgumentNullException( "element" );
*
* lock ( element.SyncRoot )
* {
* if ( !IsSafeBindable( element ) )
* throw new InvalidOperationException( "不能对元素设置InnerHTML，因为该元素不能被安全的修改内容。如果确信要改变HTML文档结构，请使用ReplaceChildsWithHtml扩展方法。" );
*
* ReplaceChildsWithHtml( element, html );
* }
* }
*
*
* /// <summary>
* /// 将元素内容替换为指定文本
* /// </summary>
* /// <param name="element">要替换的文本</param>
* /// <param name="text">要设置的文本</param>
* /// <exception cref="System.InvalidOperationException">如果元素不能被安全的修改内容</exception>
* public static void InnerText( this IHtmlElement element, string text )
* {
*
* if ( element == null )
* throw new ArgumentNullException( "element" );
*
* lock ( element.SyncRoot )
* {
* if ( !IsSafeBindable( element ) )
* throw new InvalidOperationException( "不能对元素设置InnerText，因为该元素不能被安全的修改内容。如果确信要改变HTML文档结构，请使用ReplaceChildsWithText扩展方法。" );
*
* ReplaceChildsWithText( element, text );
* }
* }
*/
/// <summary>
/// 内部方法，用于确定一个元素的内容是否可以安全数据绑定（不破坏文档结构）。
/// </summary>
/// <param name="element">要判断的元素</param>
/// <returns></returns>
internal static bool IsSafeBindable(this IHtmlElement element)
{
lock (element.SyncRoot)
{
var specification = element.Document.HtmlSpecification;
if (element.Nodes().All(n => n is IHtmlTextNode || n is IHtmlComment))//只有文本和注释的元素是可以被安全数据绑定的。
{
return(true);
}
if (!element.Nodes().All(n => n is IHtmlTextNode || n is IHtmlComment || n is IHtmlElement))//内容只能由文本、注释和元素三者组成
{
return(false);
}
var childs = element.Elements();
//如果有任何一个子元素有ID属性，那么它是不安全的
if (childs.Any(e => e.Attribute("id").Value() != null))
{
return(false);
}
//如果有任何一个子元素是不安全的，那么它是不安全的
if (childs.Any(e => e.IsSafeBindable() == false))
{
return(false);
}
//如果元素内部只有设置文本样式的子元素，那么它是安全的。
if (childs.All(e => specification.IsStylingElement(e) || specification.IsPhraseElement(e)))
{
return(true);
}
return(false);
}
}
/// <summary>
/// 尝试生成元素的HTML表现形式
/// </summary>
/// <param name="element">要生成HTML的元素</param>
/// <returns></returns>
private static string GenerateElementHtml(IHtmlElement element)
{
var builder = new StringBuilder();
if (HtmlSpecification.selfCloseTags.Contains(element.Name, StringComparer.OrdinalIgnoreCase))
{
if (element.Nodes().Any())
{
throw new FormatException(string.Format(CultureInfo.InvariantCulture, "HTML元素 {0} 不能有任何内容", element.Name));
}
builder.Append(GenerateTagHtml(element, true));
}
else
{
builder.Append(GenerateTagHtml(element, false));
element.Nodes().ForAll(node => builder.Append(GenerateHtml(node)));
builder.AppendFormat("</{0}>", element.Name);
}
return(builder.ToString());
}
/// <summary>
/// 尝试生成元素的HTML表现形式
/// </summary>
/// <param name="element">要生成HTML的元素</param>
/// <returns></returns>
private static string GenerateElementHtml(IHtmlElement element)
{
var builder = new StringBuilder();
var specification = element.Document.HtmlSpecification;
if (specification.IsForbiddenEndTag(element.Name))
{
if (element.Nodes().Any())
{
throw new FormatException(string.Format(CultureInfo.InvariantCulture, "HTML元素 {0} 不能有任何内容", element.Name));
}
builder.Append(GenerateTagHtml(element, true));
}
else
{
builder.Append(GenerateTagHtml(element, false));
element.Nodes().ForAll(node => builder.Append(GenerateHtml(node)));
builder.AppendFormat("</{0}>", element.Name);
}
return(builder.ToString());
}
public HtmlList( IHtmlElement element )
{
if ( element == null )
throw new ArgumentNullException( "element" );
if ( !HtmlSpecification.listElements.Contains( element.Name.ToLowerInvariant() ) )
throw new ArgumentException( "只能从列表元素创建 HtmlList 对象" );
if ( element.Elements().Any( e => !e.Name.EqualsIgnoreCase( "li" ) ) )
throw new FormatException( "HTML 文档格式不正确，列表元素只能包含 li 元素" );
if ( element.Nodes().OfType<IHtmlTextNode>().Any( n => !n.IsWhiteSpace() ) )
throw new FormatException( "HTML 文档格式不正确，列表元素只能包含 li 元素，不能包含文本。" );
_element = element;
}
private static void RenderElementAndChilds(IHtmlElement element, TextWriter writer, params IHtmlAdapter[] adapters)
{
if (HtmlSpecification.selfCloseTags.Contains(element.Name, StringComparer.OrdinalIgnoreCase))
{
var builder = new StringBuilder();
builder.Append(GenerateTagHtml(element, true));
if (element.Nodes().Any())
{
throw new FormatException(string.Format(CultureInfo.InvariantCulture, "HTML元素 {0} 不能有任何内容", element.Name));
}
writer.Write(builder);
}
else
{
writer.Write(GenerateTagHtml(element, false));
RenderChilds(element, writer, adapters);
writer.Write("</{0}>", element.Name);
}
}
bool ICssPseudoClassSelector.IsEligible(IHtmlElement element)
{
if (element == null)
{
throw new ArgumentNullException("element");
}
switch (_name)
{
case "only-child":
return(element.Siblings().Count() == 1);
case "only-of-type":
return(element.Siblings(element.Name).Count() == 1);
case "empty":
return(element.Nodes().Count(n => n is IHtmlElement || n is IHtmlTextNode) == 0);//只有元素和文本节点视为有内容 http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#empty-pseudo
default:
throw new InvalidOperationException();
}
}
public HtmlList(IHtmlElement element)
{
if (element == null)
{
throw new ArgumentNullException("element");
}
if (!HtmlSpecification.listElements.Contains(element.Name.ToLowerInvariant()))
{
throw new ArgumentException("只能从列表元素创建 HtmlList 对象");
}
if (element.Elements().Any(e => !e.Name.EqualsIgnoreCase("li")))
{
throw new FormatException("HTML 文档格式不正确，列表元素只能包含 li 元素");
}
if (element.Nodes().OfType <IHtmlTextNode>().Any(n => !n.IsWhiteSpace()))
{
throw new FormatException("HTML 文档格式不正确，列表元素只能包含 li 元素，不能包含文本。");
}
_element = element;
}
/// <summary>
/// 渲染元素和其子节点
/// </summary>
/// <param name="element">要渲染的元素</param>
/// <param name="context">渲染上下文</param>
private static void RenderElementAndChilds( IHtmlElement element, IHtmlRenderContext context )
{
var writer = context.Writer;
var specification = element.Document.HtmlSpecification;
if ( specification.IsForbiddenEndTag( element.Name ) )
{
var builder = new StringBuilder();
builder.Append( GenerateTagHtml( element, true ) );
if ( element.Nodes().Any() )
throw new FormatException( string.Format( CultureInfo.InvariantCulture, "HTML元素 {0} 不能有任何内容", element.Name ) );
writer.Write( builder );
}
else
{
writer.Write( GenerateTagHtml( element, false ) );
RenderChilds( element, context );
writer.Write( "</{0}>", element.Name );
}
}
/// <summary>
/// 尝试生成元素的HTML表现形式
/// </summary>
/// <param name="element">要生成HTML的元素</param>
/// <returns></returns>
private static string GenerateElementHtml( IHtmlElement element )
{
var builder = new StringBuilder();
var specification = element.Document.HtmlSpecification;
if ( specification.IsForbiddenEndTag( element.Name ) )
{
if ( element.Nodes().Any() )
throw new FormatException( string.Format( CultureInfo.InvariantCulture, "HTML元素 {0} 不能有任何内容", element.Name ) );
builder.Append( GenerateTagHtml( element, true ) );
}
else
{
builder.Append( GenerateTagHtml( element, false ) );
element.Nodes().ForAll( node => builder.Append( GenerateHtml( node ) ) );
builder.AppendFormat( "</{0}>", element.Name );
}
return builder.ToString();
}
bool ICssPseudoClassSelector.IsEligible( IHtmlElement element )
{
if ( element == null )
throw new ArgumentNullException( "element" );
switch ( _name )
{
case "only-child":
return element.Siblings().Count() == 1;
case "only-of-type":
return element.Siblings( element.Name ).Count() == 1;
case "empty":
return element.Nodes().Count( n => n is IHtmlElement || n is IHtmlTextNode ) == 0;//只有元素和文本节点视为有内容 http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#empty-pseudo
default:
throw new InvalidOperationException();
}
}
