The format of the incoming data. 
   Namespace:   Autodesk.Revit.DB  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 17.0.0.0 (17.0.1090.0) 
  Since:  2017 
Syntax
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Remarks
 If this option is set to Auto (the default), the file name extension will be used to determine the input format. That covers most file-based data import workflows. Specify the input format explicitly to perform an additional sanity check or if you are using a non-standard file extension. 
 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 |