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Snakes on a Map: Python in GIS

This DLL, when registered on each client machine as a class extension, will automatically populate the following fields.

• EventID – This will be filled with a 38 character Global Unique Identifier.
• CreatedBy – This will be filled with the current username of the logged on user at the client machine.
• CreatedDate – This will be filled with the data & time of the client machine.
• LastModified – This will be filled with the current username of the logged on user at the client machine.
• ModifiedBy – This will be filled with the data & time of the client machine.

These fields are part of the core ArcGIS Pipeline Data Model (APDM), but can be added to any geodatabase featureclass or table.  I have provided a model that will add the five fields.  The CreatedBy,  CreatedDate , and EventID will fire with the OnCreate event while the LastModified and ModifiedBy will fire with the OnChange event.

Install:

To install, place the UserDateGUID folder and all its contents into a folder of your choosing (we created a folder under the ArcGISHome directory and placed it there) on each client machine that will be opening the featureclass/table.    To register the dll simply run the included UserDateGUID_INSTALL.bat file.   Note: if the folder location changes the DLL will have to be re-registered.

There are two ways you can assign this class extension to a feature class.

• Use the Set Class Extension sample (http://resources.esri.com/help/9.3/ArcGISDesktop/com/samples/geodatabase/Extending_the_Geodatabase/ad79f981-123e-4bb0-8510-45d6dab0427d.htm).  This link has been fixed (10/2/09).
• Use the DLL GUID below.

• Or open the geodatabase in Management Studio (SQL Server) or MS Access (MDB) and open the table titled GDB_ObjectClasses. Paste the DLL GUID below (including brackets) in the EXTCLSID field for every appropriate class.

DLL GUID : {12D92D61-808A-4ADB-AFA0-3D361B2EFB03}

Note: that you may have only one class extension registered per featureclass/table.  This means that if you want the class extension to perform more the the supplied functionality you will have to modify the source code.  Also be aware that Feature-linked Annotation has a class extension registered by ArcGIS.  Therefore you won’t be able to use this class extension on Feature-linked Annotation.

Please be aware that once this class extension is registered on a feature class/table in the geodatabase, the DLL must be registered on the client machine as well.  Otherwise the featureclass/table is not viewable.  This is the case for any machine with ArcGIS Desktop (ArcMap, ArcCatalog, ArcReader) and ArcGIS Server.  We have also found this to be true for SynerGee’s Stoner software as well.

Un-Install:

To remove the class extension from a SQL/SDE GDB run the script below.

UPDATE sde.GDB_OBJECTCLASSES SET EXTCLSID = NULL WHERE EXTCLSID = '{12D92D61-808A-4ADB-AFA0-3D361B2EFB03}'

To remove it from a Personal GDB open the MDB file in Access and run a find/replace on the ObjectClassess table – EXTCLSID field.

To remove from a File Geodatabase use the link to the “Set Class Extension sample” above.

Notes:

We have been using this DLL for a couple of years on a SQL Server database with no problems.  We have registered it with 9.2, 9.3, and 9.3.1 with most service packs (we skipped a couple) in between and have never had any problems.  Just be aware that you may encounter more conflicts when working in a multi-user editing environment.  This is easily avoided by keeping editors from working on the same feature at the same time.

If for any reason you send your database to another user or support center you will need to provide them with the ability to remove the class extension from the geodatabase or provide them the DLL .  Also note that if you have it registered on a featureclass/table in ArcSDE and that featureclass/table is copied to a file or personal geodatabase, the dll will still be registered.

Credit:

This DLL is slightly modified from the one written by Evan Thoms at the following link. The only differences are that this is designed specifically for the APDM and the OnChange section was modified to fit the “modify tracking” of the APDM.

Download:

Please visit http://arcscripts.esri.com/details.asp?dbid=16597 to download.

http://resources.esri.com/geoprocessing/index.cfm?fa=codeGalleryDetails&scriptID=16473

-Mike