The top extension method option.

Namespace: Autodesk.Revit.DB.Structure
Assembly: RevitAPI (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0)
Since: 2015

Syntax

C#
`public AnalyticalAlignmentMethod TopExtensionMethod { get; set; }`

Visual Basic
`Public Property TopExtensionMethod As AnalyticalAlignmentMethod Get Set`

Visual C++
`public: property AnalyticalAlignmentMethod TopExtensionMethod { AnalyticalAlignmentMethod get (); void set (AnalyticalAlignmentMethod value); }`

Exceptions

Exception	Condition
Autodesk.Revit.Exceptions ArgumentOutOfRangeException	When setting this property: A value passed for an enumeration argument is not a member of that enumeration