I’ve been dealing with a number of item event receivers in SharePoint and I ran across the need to figure out whether or not the binary file associated with an item in a document library is being updated during the ItemUpdating event.  I knew there were some additional events in the SPItemEventReceiver class, but it turns out that none of them alert you as to when a binary file is actually being updated. 

With the simple option out, I had to turn to a more investigative approach.  So I threw in some code to write out the BeforeProperties and AfterProperties of the properties parameter passed into the ItemUpdating method to see if there was some telltale sign of a binary file update, and there were a few.

So if you want to tell whether or not the binary file has been updated in the ItemUpdating method, you just have to check if vti_docstoreversion has a null value in the AfterProperties collection.  If it has a value, then the binary file has NOT been updated.

There are some additional properties for which this appears to hold true as well:

• vti_docstoreversion
• vti_docstoretype
• vti_metainfoversion
• vti_contentversionisdirty
• vti_contenttag
• vti_modifiedby
• vti_timelastmodified

I’m not sure if they all always hold true, but they appeared to be consistent in what little testing I did.