对标题中特殊字符格式化，以便能换行显示

              public static string formatstr(string str, int len, string tag)

              {

                     char[] arrchar = new char[10]{ '。','，','~','！','、','？','*','…','￥','$'};

                     stringbuilder sb = new stringbuilder();

                     int i = 0;

                     foreach (char char in str)

                     {

                            bool biscontain = false;

                            for(int j = 0; j < arrchar.length; j++)

                            {

                                   if(char.compareto(arrchar[j]) == 0)

                                   {

                                          biscontain = true;

                                          break;

                                   }

                            }

                            if ((int)char <= 127 || biscontain)

                                   i += 1;

                            else

                                   i = 0;

                            sb.append(convert.tostring(char));

                            if(i > len)

                            {

                                   sb.append(tag);

                                   i = 0;

                            }

                     }

                     return sb.tostring();

              }