public IEnumerable<DataFile> FindDataFiles(string directory, string searchPattern)
{
string fullPath = Path.Combine(dataFolder, directory);
if (Directory.Exists(fullPath))
{
foreach (string file in Directory.EnumerateFiles(fullPath, searchPattern))
{
yield return new DataFile(this, FileMode.Open, file, Path.Combine(directory, Path.GetFileName(file)));
}
}
}