static IEnumerable <ClientVersion> LoadClientVersionsOrDefaults(string fileName)
{
if (fileName == null)
{
throw new ArgumentNullException("fileName");
}
IEnumerable <ClientVersion> clientVersions = null;
try
{
// Load client versions from file
if (File.Exists(fileName))
{
var xml = XDocument.Load(fileName);
var root = xml.Descendants("SupportedClients").FirstOrDefault();
if (root != null)
{
var fileVersionString = (string)root.Attribute("FileVersion");
// Parse the versions for comparison
var fileVersion = Version.Parse(fileVersionString);
var latestVersion = Version.Parse(App.ClientVersionsFileVersion);
clientVersions = ClientVersionSerializer.DeserializeAll(xml);
// Check if client version file is out of date
if (fileVersion < latestVersion)
{
Debug.WriteLine(string.Format("Migrating supported client versions... ({0} -> {1})", fileVersion, latestVersion));
// Perform a migration (union) of the old and new client versions
if (clientVersions != null)
{
clientVersions = clientVersions.Union(ClientVersion.GetDefaultVersions(), ClientVersion.VersionComparer);
}
}
}
}
}
catch (Exception ex)
{
Debug.WriteLine(string.Format("Unable to load client versions: {0}", ex.Message));
clientVersions = null;
}
// Use the deserialized client versions (or the defaults)
return(clientVersions ?? ClientVersion.GetDefaultVersions());
}