/// <summary>
/// Validates a comic book on the server
/// before adding a new record or updating an existing record.
/// </summary>
/// <param name="comicBook">The comic book to validate.</param>
private void ValidateComicBook(ComicBook comicBook)
{
// If there aren't any "SeriesId" and "IssueNumber" field validation errors...
if (ModelState.IsValidField("ComicBook.SeriesId") &&
ModelState.IsValidField("ComicBook.IssueNumber"))
{
// Then make sure that the provided issue number is unique for the provided series.
if (_comicBooksRepository.SeriesHasIssueNumber(comicBook.Id, comicBook.SeriesId, comicBook.IssueNumber))
{
ModelState.AddModelError("ComicBook.IssueNumber",
"The provided Issue Number has already been entered for the selected Series.");
}
}
}