I build a plugin that runs in account update message that makes some validation not to duplicate the record. But if I try to disable that account or merge with another one it triggers the plugin.
How can I tell if the plugin was triggered by an activate/deactivate/merge action, or event mode like the one in CRM Dynamics 2011 Save Event Arguments Reference?
To add to Pete Oakey's answer, you can actually tell your plugin to fire only when certain fields are changed at the registration phase, in addition to testing this in actual code @ runtime, by changing the "Filtering Attributes" of the plugin step. So unless your validation logic specifically needs the StateCode/StatusCode attributes to correctly process, you can filter those two attributes out, or just include the attributes your validation logic needs.
Original answer:
I believe you can reference the IExecutionContext.Depth Property of the IPluginExecutionContext object.
Every time a running plug-in or Workflow issues a message request to the Web services that triggers another plug-in or Workflow to execute, the Depth property of the execution context is increased. If the depth property increments to its maximum value within the configured time limit, the platform considers this behavior an infinite loop and further plug-in or Workflow execution is aborted. The maximum depth (8) and time limit (one hour) are configurable by the Microsoft Dynamics CRM administrator.
So you can use an if statement to check if Depth > 1.
One way would be to compare the before and after values of what's changed on the account entity in the plugin. For example if you have only have active (if that's the right property name) in the values - you can look at the after value to see what's happened.
Another way would be to add a specific plugin for these messages and set some property/flag which you can check in the update plugin. Obviously this would have to run before the update plugin.
