public bool Exist(long datasetid, long datasetVersionid, DataRepository dataRepository)
{
// check directory
string d = GetDirectoryPath(datasetid, dataRepository);
if (!Directory.Exists(d)) return false;
//check file
string file = GetZipFileName(datasetid, datasetVersionid);
string filePath = Path.Combine(d, file);
if (File.Exists(filePath)) return true;
return false;
}