Capturar mensagens de erro de DbEntityValidationException - Facebook - https://www.facebook.com/guilherme.stracini/posts/3007064412683796:5

DbEntityValidationExceptionParser.cs

public static string Parse(this DbEntityValidationException e)
{
    var builder = new StringBuilder();
    foreach (var eve in e.EntityValidationErrors)
    {
        builder.AppendFormat("Entity type: {0} | State: {1}",eve.Entry.Entity.GetType().Name,eve.Entry.State);
        foreach (var ve in eve.ValidationErrors)
            builder.AppendFormat("Property name: {0} | Current value: {1} | Error message: {2}",
                ve.PropertyName,
                eve.Entry.CurrentValues.GetValue<Object>(ve.PropertyName),
                ve.ErrorMessage);
    }
    return builder.ToString();
}

//Just add this method in a static class.
//Then just call it with the DbEntityValidationException inside a try/catch block to get the message.
//
//try {
//    _db.SaveChanges();
//} catch(DbEntityValidationException e) {
//   var message = e.Parse();
//   //do what you want with message variable (log or show to the user - do not show this in a production environment!)
//}