在字符串中找含HTTP连接字符串的代码

      代码如下：

      private string GetHttpStr(string str, string httpStr)
        {
            bool Ishavevalue = false;
            int newlength = httpStr.Length;
            string newstr = null;

            string httpendString = "<";
             if (str.Length >= newlength && str.Contains(httpStr))
            {
                newstr = str.Substring(str.IndexOf(httpStr, StringComparison.OrdinalIgnoreCase) + newlength);
            }
            int startindex = 0;
            startindex = str.IndexOf(httpStr, StringComparison.OrdinalIgnoreCase);
            int lengthindex = 0;
            string returnvalue = null;
            if (startindex >= 0)
            {
                if (newstr.IndexOf('"') != -1 && newstr.IndexOf('"') <= newstr.IndexOf(httpendString))
                {
                    lengthindex = newstr.IndexOf('"') + newlength;
                }
                else if (newstr.IndexOf('"') == -1 && newstr.IndexOf(httpendString) == -1)
                {
                    lengthindex = str.Length;
                }
                else
                {
                    lengthindex = newstr.IndexOf(httpendString) + newlength;
                }
                if (lengthindex == (newlength - 1))
                {

                    lengthindex = newstr.IndexOf(httpendString) + newlength;
                }
                returnvalue = str.Substring(startindex, lengthindex);
                Ishavevalue = true;
            }
            returnvalue = ReplaceSpecialUrl(returnvalue);
            return returnvalue + "  " + ((startindex + lengthindex) < str.Length && startindex > 0 && Ishavevalue ? GetHttpStr(str.Substring(startindex + lengthindex), httpStr) : null);

        }

因为HTTP连接在html都是以"结束或者<结束，所以根据传入的httpStr样式不区分大小写方式把字符串str含有的以递归的方式找出来。