SPChangeTokenCollection class

This collection is provided so that you can easily manage change logs at the Web application level. Each content database in a Web application maintains its own change log. If you want a consolidated change report for multiple content databases, you can use an SPChangeTokenCollection object to store change tokens for all databases in a single collection. Once you have a collection of change tokens, you can enumerate the collection and ask each database in turn for its changes by calling the GetChanges(SPChangeToken) method. You can also serialize a collection using the ToString() method, and store it on disk. Later, when you want to revisit the change logs, you can reconstruct the collection using a variation of the constructor that accepts a string argument, and then use the deserialized change token collection to query the change logs again.

The following example is a console application that queries the change log for each content database in a Web application. On the program’s first run, all changes are retrieved from each log. After processing each collection of changes, the program saves the last change token in the change collection to an SPChangeTokenCollection collection. When all logs have been processed, the SPChangeTokenCollection object is serialized, and the resulting string is stored in a file on disk.

On subsequent runs of the program, the data file is read, the string representation of the collection is retrieved, and the SPChangeTokenCollection object is reconstructed. The change tokens in the collection are then used to fetch changes made since the last run of the program.

This example makes no attempt to save the information that it retrieves from the change logs. It simply prints the output to the console. A useful enhancement would be to add code for consolidating changes in a file or database, where they could be subjected to further analysis.

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