Best thing in these cases is to use the Label data type.

thanks, didnt see that one :-)

Do you know how you can restrict the saved Umbraco event to fire only on one doc type?

You can inspect the entities in the event data for the ContentType (Document Type) Alias and then use that to restrict your code to a specific Document Type - you can also inspect the properties to see if a specific property exists on the entity, or has a value etc.

E.g.:

    void ContentService_Saving(IContentService sender, Umbraco.Core.Events.SaveEventArgs<Umbraco.Core.Models.IContent> e)
    {
        foreach (var article in e.SavedEntities)
        {
            if (article.ContentType.Alias == "Article")
            {
                // Check for Post Date and set to current date if not already set.
                if (article.HasProperty("datePosted"))
                {
                    DateTime? datePosted = article.GetValue<DateTime?>("datePosted");
                    if (!datePosted.HasValue)
                        article.SetValue("datePosted", DateTime.Now);

                }
            }
        }
    }

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