Checks if given Reference identifies either a valid element or subelement. 
   Namespace:   Autodesk.Revit.DB  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 18.0.0.0 (18.2.0.0) 
  Since:  2018 
Syntax
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Parameters
- aDoc
 -  Type:  Autodesk.Revit.DB Document  
The document. 
- reference
 -  Type:  Autodesk.Revit.DB Reference  
The reference that identifies an element or subelement. 
Return Value
True if %reference% identifies a valid element or subelement, false otherwise.Remarks
 A reference to an element or subelement in a linked document is acceptable. 
 Exceptions
| Exception | Condition | 
|---|---|
| Autodesk.Revit.Exceptions ArgumentNullException | A non-optional argument was NULL |