public void SetSitesThatDoNotExist()
{
SitesThatDoNotExist = DataInFile.Where(d => !Sites.Any(s => s.Name == d.Site)).AsEnumerable();
}
public void SetClientsThatDoNotExist()
{
ClientsThatDoNotExist = DataInFile.Where(d => !Clients.Any(c => c.Id == d.ClientId)).AsEnumerable();
}