com.smartgwt.client.widgets.tree.events

## Interface DataChangedHandler

- All Superinterfaces:
    com.google.gwt.event.shared.EventHandler

      public interface DataChangedHandler
      extends com.google.gwt.event.shared.EventHandler

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `onDataChanged(DataChangedEvent event)` Notification method fired when the TreeGrid's data changes, for any reason.

- - ### Method Detail

    - #### onDataChanged

          void onDataChanged(DataChangedEvent event)

      Notification method fired when the TreeGrid's data changes, for any reason.

      Examples of why data changed might be:

      - a call to `addData()`, `updateData()`, or `removeData()`
      - `DataSource` updates from the server for `ResultTree` data (triggered by record editing, etc.)
      - fetches arriving back from the server for `ResultTree` data
      - programmatic changes to `Tree` data if made through APIs such as `Tree.add()`, `Tree.remove()`, etc.
      - cache invalidation
      - filtering
      Calling `setData()` doesn't call this notification directly, but it may fire if one of the above listed events is triggered (e.g. a server fetch for `ResultTree` data).

      Note that the `operationType` parameter is optional and will be passed and contain the operation (e.g. "update") if this notification was triggered by a fetch, an `addData()`, `updateData()`, or `removeData()`, or a `DataSource` update for `ResultTree` data (the first three reasons listed above) but otherwise will be null.

      Parameters:
        `event` - the event