Save int value to .txt file

If you're using C# you could also look at:

 System.IO.File.WriteAllText(path, value)
 System.IO.File.ReadAllText(path)

...but you probably want something like this to serialize your object first:

    public string SerializeXml<T>(T value) {
       if(value == null) {
         return null;
       }
 
       XmlSerializer serializer = new XmlSerializer(typeof(T));
 
       XmlWriterSettings settings = new XmlWriterSettings();
       settings.Encoding = new UnicodeEncoding(false, false); // no BOM in a .NET string
       settings.Indent = false;
       settings.OmitXmlDeclaration = false;
 
       using(StringWriter textWriter = new StringWriter()) {
         using(XmlWriter xmlWriter = XmlWriter.Create(textWriter, settings)) {
           serializer.Serialize(xmlWriter, value);
         }
         return textWriter.ToString();
       }
     }
 
     public T DeserializeXml<T>(string xml) {
       if(string.IsNullOrEmpty(xml)) {
         return default(T);
       }
 
       XmlSerializer serializer = new XmlSerializer(typeof(T));
 
       XmlReaderSettings settings = new XmlReaderSettings();
 
       using(StringReader textReader = new StringReader(xml)) {
         using(XmlReader xmlReader = XmlReader.Create(textReader, settings)) {
           return (T) serializer.Deserialize(xmlReader);
         }
       }
     }