Opc.Ua.Security.SecurityConfigurationManager.WriteConfiguration C# (CSharp) Method

        public void WriteConfiguration(string filePath, SecuredApplication configuration)
        {
            if (configuration == null) throw new ArgumentNullException("configuration");

            // check for valid file.
            if (String.IsNullOrEmpty(filePath) || !File.Exists(filePath))
            {
                throw ServiceResultException.Create(
                    StatusCodes.BadNotReadable,
                    "Cannot find the configuration file: {0}",
                    configuration.ConfigurationFile);
            }

            // load from file.
            XmlDocument document = new XmlDocument();
            document.Load(new FileStream(filePath, FileMode.Open));

            XmlElement element = Find(document.DocumentElement, "SecuredApplication", Namespaces.OpcUaSecurity);

            // update secured application.
            if (element != null)
            {
                configuration.LastExportTime = DateTime.UtcNow;
                element.InnerXml = SetObject(typeof(SecuredApplication), configuration);
            }
            
            // update application configuration.
            else
            {
                UpdateDocument(document.DocumentElement, configuration);
            }

            try
            {
                // update configuration file.
                Stream ostrm = File.Open(filePath, FileMode.Create, FileAccess.Write);
                StreamWriter writer = new StreamWriter(ostrm, System.Text.Encoding.UTF8);
                
                try
                {
                    document.Save(writer);
                }
                finally
                {
                    writer.Flush();
                    writer.Dispose();
                }
            }
            catch (Exception e)
            {
                throw ServiceResultException.Create(
                    StatusCodes.BadNotWritable,
                    e,
                    "Cannot update the configuration file: {0}",
                    configuration.ConfigurationFile);
            }
        }
        #endregion