title: Is it safe to allow two threads to edit different properties of the same object at the same time?
body: <p>I am writing a cataloging application that parses through and extracts information from files and stores the information from each file in an object instance. In addition to the data extracted from the file the objects also have additional meta data properties (author, tags, notes, etc..) which later get stored in a separate XML file.</p>
  
  <p>Extracting the data from the files is a time consuming process so I have it running on a separate thread. The properties extracted from the files will only ever come from the files, and thus have [ReadOnly] attributes to prevent the user from editing them. The meta data properties on the other hand are only populated by the user and thus are not read only. I'm allowing the user to view/edit these object through a PropertyGrid.</p>
  
  <p>So if the extraction process is running on one thread populating the file properties of an object, is there any danger in letting the user edit the meta data properties at the same time? I'm trying to decided if I should use a modal interface that prevents the user from doing anything until the extraction is complete/canceled, or a non-modal interface that allows them to continue working while the extraction is running.</p>