Forces the entire System.Web.UI.StateManagedCollection collection to be serialized into view state.
The StateManagedCollection.SetDirty method forces the System.Web.UI.StateManagedCollection collection to be serialized completely (whereas the System.Web.UI.StateManagedCollection.System.Web.UI.IStateManager.SaveViewState method saves only the change information). This is useful when a collection has changed in a significant way and change information is insufficient to recreate the object in memory from view state.