public static bool existElement(string html, string tag, out string outVal)
{
outVal = null;
HtmlTagClass ret = HtmlTagClass.getTagInfo(html, tag);
if (ret == null)
{
return(false);
}
outVal = ret.AttValue;
return(true);
}
public static HtmlTagClass getTagInfo(string html, string tag)
{
HtmlTagClass ret = new HtmlTagClass();
string[] arr = tag.Split('|'); //p|class|lkjlfd
string tagName = arr[0]; //tag p ，a，table ，td，div
string tagKeyType = ""; //class ,id,name
string tagKeyValue = ""; //
string tagValAtt = "";
if (arr.Length > 1)
{
tagKeyType = arr[1];
}
if (arr.Length > 2)
{
tagKeyValue = arr[2];//除去 tag 和 约束[id|name]的值
}
if (arr.Length > 3)
{
tagValAtt = tag.Substring(tagName.Length + 1 + tagKeyType.Length + 1 + tagKeyValue.Length + 1);
}
ret.TagName = tagName;
ret.KeyName = tagKeyType;
ret.KeyValue = tagKeyValue;
ret.AttName = tagValAtt;
string strReg = string.Format(@"<{0}[^>]+>", tagName);
Regex reg = new Regex(strReg);//查找所有的符合标志的记录
MatchCollection matchs = reg.Matches(html);
XmlDocument xmldoc = new XmlDocument();
for (int i = 0; i < matchs.Count; i++)
{
string xml = matchs[i].Value;
try
{
xmldoc.LoadXml(xml);
}
catch
{
if (!xml.EndsWith("/>"))
{
xml = xml.Substring(0, xml.Length - 1) + "/>";
}
try
{
xmldoc.LoadXml(xml);
}
catch
{
continue;
}
}
XmlNode node = xmldoc.SelectSingleNode(string.Format("{0}[@{1}='{2}']", tagName, tagKeyType, tagKeyValue));
if (node != null)
{
ret.AttValue = node.Attributes[tagValAtt]?.Value;
return(ret);
}
}
return(null);
}