(文章如何截取前几行作为列表摘要)无损返回HTML代码


/* 时间很久远了,有码友要,我抄了下来,记得使用的时候还是有部分例外情况要处理,大部分是ok的。 * 函数: * 说明:无损返回HTML代码 * * 作者:卡斯Kas(QQ:10590916) * 修改:2010-12-13、 */ public static string LeftH(string str, int l) { //为了防止错误 string odstr = str; bool isHtml = false;//判断截取开头是否是字符串 int maxLen = str.Length; int n = 0, i = 0, b = 0, e = 0; string c, c2 = "", Start = "", EndLabel = "", AllLabel = ""; if (l >= str.Length) return str;//截取字段大于字符长度 bool isErr = false; try { while (n < l && i < maxLen) { //1 i++; c = str.Substring(i - 1, 1); string end2str = ""; try { end2str = str.Substring(i - 1, 2); } catch { end2str = ""; } if (c == "<" && end2str != "</") { isHtml = true; b = i;//记录一个位置 //5 解决非成对标签 string end2tag = ""; try { end2tag = str.Substring(i, 2); } catch { end2tag = ""; } if (end2tag == "br") { isHtml = false; } if (str.Substring(i, 1).ToLower() == "%") { isHtml = false; } if (str.Substring(i, 1).ToLower() == "?") { isHtml = false; } else if (end2tag == "hr") { isHtml = false; } //5end } //1end //2 if (c == "<" && end2str == "</") { c2 = str.Substring(i - 1, str.Substring(i - 1).IndexOf(">") + 1); AllLabel = AllLabel.Substring(c2.Length); } //2end Start = Start + c;//记录当前字符及其前面字符 if (!isHtml) { //6 较为准确的计数 try { if (str.Substring(i, 2).ToLower() == "br") { } else if (str.Substring(i, 2).ToLower() == "hr") { } else { n++; } } catch { //如果出错,则返回纯文本(@"<[^>]+>|</[^>]+>"); //odstr = Regex.Replace(odstr, @"<[^>]+>|</[^>]+>", "", RegexOptions.IgnoreCase); odstr = odstr.Replace("<", "<").Replace(">", ">"); if (l > odstr.Length) l = odstr.Length; return odstr.Substring(0, l); } //6end } else { if (c == ">")//如果循环到>时,要处理的成对标签中间部分 { if (isHtml) { EndLabel = str.Substring(b, i - b);//获取<到>之间的代码 e = EndLabel.IndexOf(" ");//标签属性都有空格,以空格为分割,获取标签名 if (e > 0) { EndLabel = "</" + EndLabel.Substring(0, e) + ">"; } else { EndLabel = "</" + EndLabel; } AllLabel = EndLabel + AllLabel;//记录当前结束标签,及所有有关结束标签 } isHtml = false;//重置属性,从新开始 } } //4 当结束时,发现有未闭合的标签,则重新来一次 if (n + 1 >= l) { if (InStrN(Start, "<") != InStrN(Start, ">")) { n--; } } //4end }//end while } catch { isErr = true; } string newReString = Start + AllLabel + "..."; //最后再次验证 Regex Rg = new Regex("<.[^>/]+>", RegexOptions.Compiled); Regex Rg2 = new Regex(@"<\s*/[a-z]\s*>", RegexOptions.Compiled); if (inStrLen(newReString, "<") != inStrLen(newReString, ">")) { isErr = true; } else if (inStrLen(newReString.Replace(""", "\""), "\"") % 2 == 1) { isErr = true; } else if (Rg.Matches(newReString).Count != Rg2.Matches(newReString).Count) { isErr = true; } if (isErr) { odstr = odstr.Replace("<", "<").Replace(">", ">").Replace("\"", """).Replace("'", "'"); if (l > odstr.Length) { newReString = odstr; } else { try { newReString = odstr.Substring(0, l) + "..."; } catch { newReString = odstr; } } } return newReString;//返回 }

 

 

posted @ 2012-07-01 21:54  张三封  阅读(919)  评论(2编辑  收藏  举报