Entity Framework validation

When Entity Framework attempts to save an entity and the validation fails, db.SaveChanges() will throw a generic exception.

You can use KissLogConfiguration.Options.AppendExceptionDetails handler to intercept the validation exception and log the validation errors.

private static void ConfigureKissLog()
{
    KissLogConfiguration.Options
        .AppendExceptionDetails((Exception ex) =>
        {
            StringBuilder sb = new StringBuilder();

            if (ex is System.Data.Entity.Validation.DbEntityValidationException dbException)
            {
                sb.AppendLine(">>> Validation exceptions:");

                foreach (var error in dbException.EntityValidationErrors.SelectMany(p => p.ValidationErrors))
                {
                    string message = string.Format("Field: {0}, Error: {1}", error.PropertyName, error.ErrorMessage);
                    sb.AppendLine(message);
                }
            }

            return sb.ToString();
        });

    KissLogConfiguration.Listeners
        .Add(new LocalTextFileListener("logs", FlushTrigger.OnFlush));
}