常用字符串截取类

public int index(string content,string str)
 {
     return content.IndexOf(str);
 }

 public int index(string content, string str, int fromindex)
 {
     return content.IndexOf(str, fromindex);
 
 }

 public int strlen(string content,string start, string end)
 {
     return index(content, end) - index(content, start);
 }

 public int strlen(string content, string start,string end,int fromindex,int fromendindex)
 {
     int endindex = index(content, end, fromendindex);
     int startindex=index(content, start,fromindex);
     return endindex - startindex;
 }
 
 /// <summary>
 /// 截取字符串
 /// </summary>
 /// <param name="content">完整的内容</param>
 /// <param name="start">开始子字符串</param>
 /// <param name="startoffset">设置开始字符串的偏移量,一般为0即可</param>
 /// <param name="end">结束子字符串</param>
 /// <param name="endoffset">结束子字符串的偏移量,一般为0即可</param>
 /// <param name="fromindex">起始的搜索未知,通常为0即可,若内容中有多个匹配,可设置此参数来达过滤</param>
 /// <param name="fromendindex">同上</param>
 /// <returns>返回开始子字符串和结束子字符串中间的内容,包含开始子字符串和结束子字符串</returns>
 public string cutstr(string content, string start, int startoffset,string end,int endoffset,int fromindex,int fromendindex)
 {
     int startindex = index(content, start,fromindex)+startoffset;
     int len = strlen(content, start, end,fromindex,fromendindex)-startoffset+endoffset;
     return content.Substring(startindex, len+end.Length);
 }