'Declaration Public ReadOnly Property ItemList As LookupItemList
public LookupItemList ItemList {get;}
'Declaration Public ReadOnly Property ItemList As LookupItemList
public LookupItemList ItemList {get;}
When ItemListType is set to ItemListTypeEnum.FixedValues only the LookupItem.Value property is used, which defines a possible value that can be entered in a column by selecting it from the list.
If ItemListType value is ItemListTypeEnum.FixedLookup then list represents a lookup, where LookupItem.Value represents a key that is matched against a column value, and LookupItem.DisplayValue defines a string that will be displayed instead of an actual column value.