'Declaration Public Property AllowSorting As Nullable(Of Boolean)
public Nullable<bool> AllowSorting {get; set;}
This property defaults to null and if left null will cause the AllowSortingResolved property to resolve to true unless the field is unbound or alternate bound and the FieldLayoutSettings.SortEvaluationMode is set to 'UseCollectionView' and the Field's FieldItem.Name does not match a property on the data item that returns a data type that implements the System.IComparable interface.
Note: Even if AllowSortingResolved resolves to true the LabelClickActionResolved property determines if a click on the field's label performs a sort.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2