Node attribute value replace exception to get program?

Question

I am trying to create a program that will search for xml files for nodes in the form <disp-formula id="deqnX-Y">, create a dictionary where the keys look like rid="deqnX" ... rid="deqnY", (where X increases by +1 until it reaches Y ), and their corresponding value mappings are similar to rid="deqnX-Y"each. Then I can just do a search and replace with a dictionary to change the link nodes. that is, if the file has nodes such as <disp-formula id="deqn5-7">, <disp-formula id="deqn9-11">, <disp-formula id="deqn3a-3c">, <disp-formula id="deqn4p-5b">, and there are link nodes in the form

<xref ref-type="disp-formula" rid="deqn5">
<xref ref-type="disp-formula" rid="deqn6">
<xref ref-type="disp-formula" rid="deqn10">
<xref ref-type="disp-formula" rid="deqn5c">

which should be changed to

<xref ref-type="disp-formula" rid="deqn5-7">
<xref ref-type="disp-formula" rid="deqn5-7">
<xref ref-type="disp-formula" rid="deqn9-11">
<xref ref-type="disp-formula" rid="deqn4p-5b">

I am using the code below

void Button1Click(object sender, EventArgs e)
        {
            string active_filename = "";
            string DirectoriesName = textBox1.Text;
            string[] path = Directory.GetDirectories(DirectoriesName, "xml", SearchOption.AllDirectories)
                .SelectMany(x => Directory.GetFiles(x, "*.xml", SearchOption.AllDirectories)).ToArray();
            Dictionary<string, string> dict = new Dictionary<string, string> ();
            var re = new Regex(@"deqn(\w+)-(\w+)");
            foreach (var file in path)
            {
                dict.Clear();
                active_filename = file;
                XDocument doc = XDocument.Load(file, LoadOptions.PreserveWhitespace);
                IEnumerable<XAttribute> list_of_elements = doc.Descendants("disp-formula").Where(z => (z.Attribute("id") != null) && re.IsMatch(z.Attribute("id").Value)).Attributes("id");

                foreach (XAttribute ele in list_of_elements)
                {
                    int from = 0, to = 0;

                    string strform = re.Match(ele.Value).Groups[1].Value;

                    string strTo = re.Match(ele.Value).Groups[2].Value;

                    Boolean bfrom = int.TryParse(strform,out from);
                    Boolean bto  = int.TryParse(strTo,out to);
                    if (bfrom && bto)
                    {
                        for (int i = from; i <= to; i++)
                            dict.Add("rid=\"deqn" + i + "\"", "rid=\"" + ele.Value + "\"");
                    }
                    else {
                        for (int i = base36toInt(strform); i <= base36toInt(strTo); i++)
                        {
                            int temp = 0;
                            if (!int.TryParse(IntTo36Base(i), out temp))
                            {
                                dict.Add("rid=\"deqn" + IntTo36Base(i) + "\"", "rid=\"" + ele.Value + "\"");
                            }
                        }
                    }
                    foreach (KeyValuePair<string, string> element in dict)
                    {
                        //do a search all replace all (search Key and replace by Value
                        string text = File.ReadAllText(file);
                        text = text.Replace(element.Key, element.Value);
                        File.WriteAllText(file, text);
                    }
                }
            }
            MessageBox.Show("Done");

        }
        public static int base36toInt(string s)
        {
            char[] baseChars = "0123456789abcdefghijklmnopqrstuvwxyz".ToCharArray();
            char[] target = s.ToCharArray();
            double result = 0;
            for (int i = 0; i < target.Length; i++)
            {
                result += Array.IndexOf(baseChars, target[i]) * Math.Pow(baseChars.Length, target.Length - i - 1);
            }
            return Convert.ToInt32(result);
        }
        public static string IntTo36Base(int value)
        {
            char[] baseChars = "0123456789abcdefghijklmnopqrstuvwxyz".ToCharArray();
            string result = string.Empty;
            int targetBase = baseChars.Length;
            do
            {
                result = baseChars[value % targetBase] + result;
                value = value / targetBase;
            }
            while (value > 0);

            return result;
        }

, , <disp-formula id="deqn5-7c"> <disp-formula id="deqn2a-4">. , , System.IO.IOException: . .

, , , <disp-formula id="deqn5-7c"> / <disp-formula id="deqn2a-4">, ?

Answer 1

, , ... ? , "deqn", - , "-", - . , "deqnasdf-zxcv", .

: "deqn (\ d +) - (\ d +)" - , " -" " ". , , , deqn1-2c, . , , , .

Answer 2

:

System.IO.IOException: .

, , , , . , , , . , . , , , Process Explorer.

:

:

foreach (KeyValuePair<string, string> element in dict)
{
  //do a search all replace all (search Key and replace by Value
  string text = File.ReadAllText(file);
  text = text.Replace(element.Key, element.Value);
  File.WriteAllText(file, text);
}

:

string text = File.ReadAllText(file);
foreach (KeyValuePair<string, string> element in dict)
{
  //do a search all replace all (search Key and replace by Value
  text = text.Replace(element.Key, element.Value);
}
File.WriteAllText(file, text);