Indicates if this dimension is valid. 
   Namespace:   Autodesk.Revit.DB  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 19.0.0.0 (19.0.0.405) 
  Since:  2019 
Syntax
Remarks
 This property always returns true for model dimensions. It can return false for view-specific dimensions that are hidden because they are in an invalid state. An example of an invalid state is having misaligned references for an aligned dimension.