DbEntityValidationException with useful message returned for logging to Elmah.

gistfile1.txt

Example Response Message

Validation failed for one or more entities. See 'EntityValidationErrors' property for more details. The validation errors are: [Entity: tUser, Property: CreatedBy] The CreatedBy field is required.; [Entity: tGroup, Property: CreatedBy] The CreatedBy field is required.

UnitOfWork.cs

public void Save()
{
    try
    {
        context.SaveChanges();
    }
    catch(DbEntityValidationException ex)
    {
        var errorMessages = (from eve in ex.EntityValidationErrors
            let entity = eve.Entry.Entity.GetType().Name
            from ev in eve.ValidationErrors
            select new
            {
                Entity = entity,
                PropertyName = ev.PropertyName,
                ErrorMessage = ev.ErrorMessage
            });

        var fullErrorMessage = string.Join("; ", errorMessages.Select(e => string.Format("[Entity: {0}, Property: {1}] {2}", e.Entity, e.PropertyName, e.ErrorMessage)));

        var exceptionMessage = string.Concat(ex.Message, " The validation errors are: ", fullErrorMessage);

        throw new DbEntityValidationException(exceptionMessage, ex.EntityValidationErrors);
    }
}

Only downside to this is that you lose your stacktrace. The plus side is, you know exactly what is failing, which I feel is far more useful.