StringHelper类，内容截取，特别适合资讯展示列表

public class StringHelper
{
/// <summary>
/// 截字符串
/// </summary>
/// <param name="sInString">字符串</param>
/// <param name="iCutLength">截几个字</param>
/// <returns>截好的字符串</returns>
public static string CutStr(object sInStrings, int iCutLength)
{

string sInString = sInStrings.ToString();
if (sInString == null || sInString.Length == 0 || iCutLength <= 0) return "";
int iCount = System.Text.Encoding.Default.GetByteCount(sInString);
if (iCount > iCutLength)
{
int iLength = 0;
for (int i = 0; i < sInString.Length; i++)
{
int iCharLength = System.Text.Encoding.Default.GetByteCount(new char[] { sInString[i] });
iLength += iCharLength;
if (iLength == iCutLength)
//需要截取的和总字符串位数相等
{
sInString = sInString.Substring(0, i + 1);
break;
}
else if (iLength > iCutLength)//需要截取的小于总字符长度
{
sInString = sInString.Substring(0, i) + "...";//。。。
break;
}
}
}
return sInString;
}

/// <summary>
/// 按字节长度截取字符串(支持截取带HTML代码样式的字符串)
/// </summary>
/// <param name=”param”>将要截取的字符串参数</param>
/// <param name=”length”>截取的字节长度</param>
/// <param name=”end”>字符串末尾补上的字符串</param>此处写死了，可放开
/// <returns>返回截取后的字符串</returns>
public static string SubstringToHTML(string param, int length)
{
string end = "...";
string Pattern = null;
MatchCollection m = null;
StringBuilder result = new StringBuilder();
int n = 0;
char temp;
bool isCode = false; //是不是HTML代码
bool isHTML = false; //是不是HTML特殊字符,如&nbsp;
char[] pchar = param.ToCharArray();
for (int i = 0; i < pchar.Length; i++)
{
temp = pchar[i];
if (temp == '<')
{
isCode = true;
}
else if (temp == '&')
{
isHTML = true;
}
else if (temp == '>' && isCode)
{
n -= 1;
isCode = false;
}
else if (temp == ';' && isHTML)
{
isHTML = false;
}

if (!isCode && !isHTML)
{
n = n + 1;
//UNICODE码字符占两个字节
if (System.Text.Encoding.Default.GetBytes(temp + "").Length > 1)
{
n = n + 1;
}
}

result.Append(temp);
if (n >= length)
{
break;
}
}
result.Append(end);
//取出截取字符串中的HTML标记
string temp_result = result.ToString().Replace("(>)[^<>]*(<?)", "$1$2");
//去掉不需要结素标记的HTML标记
temp_result = temp_result.Replace(@"</?(AREA|BASE|BASEFONT|BODY|BR|COL|COLGROUP|DD|DT|FRAME|HEAD|HR|HTML

|IMG|INPUT|ISINDEX|LI|LINK|META|OPTION|P|PARAM|TBODY|TD|TFOOT|TH|THEAD

|TR|area|base|basefont|body|br|col|colgroup|dd|dt|frame|head|hr|html|img|input|isindex|li|link|meta

|option|p|param|tbody|td|tfoot|th|thead|tr)[^<>]*/?>",
"");
//去掉成对的HTML标记
temp_result = temp_result.Replace(@"<([a-zA-Z]+)[^<>]*>(.*?)</1>", "$2");
//用正则表达式取出标记
Pattern = ("<([a-zA-Z]+)[^<>]*>");
m = Regex.Matches(temp_result, Pattern);
ArrayList endHTML = new ArrayList();
foreach (Match mt in m)
{
endHTML.Add(mt.Result("$1"));
}
//补全不成对的HTML标记
for (int i = endHTML.Count - 1; i >= 0; i--)
{
result.Append("</");
result.Append(endHTML[i]);
result.Append(">");
}
return result.ToString();
}

}
}