episerver epiessentials
EpiEssentials ContentAreaMaxItems
Limit how many items can go into a content area.
To use, put the attribute on your property:
[Display(Name = "Items", Description = "max 3 items",
GroupName = SystemTabNames.Content, Order = 1)]
[AllowedTypes(typeof(ItemBlock))]
[ContentAreaMaxItems(3)]
public virtual ContentArea Items{ get; set; }