cleanup tasks from workflows and deleted items

Question

We have workflow associated to a list. The workflow is complicated and has many tasks on it.

I noticed that the Workflow tasks still exists even if you delete the associated item. or when you cancel the workflow.

I would like to know if this is a common problem and how can I fix>?

Options 1. Create a site collection workflow that runs everyday and basically looking orphan tasks. On the same loop check that if the associated workflow is cancelled.

Answer 1

Another option is to code the cleaning logic in a timer job.

Create a timer job that runs daily/weekly/monthly (night hours), loop through the tasks list and delete orphan tasks and tasks of canceled workflows.

1.) Delete orphan tasks

Tasks created by workflows started on list items have field ‘WorkflowListId’ that contains the Guid of the list and field ‘WorkflowItemId’ that contains the ID of the associated list item.

Tasks created otherwise (not by list workflows) have null in ‘WorkflowListId’ and ‘WorkflowItemId’.

You can use these two fields to get only the workflow tasks and if there is no item with that ID in the list (the item has been deleted) then delete the task.

2.) Delete tasks of terminated workflows

You can get the workflow status and if it is stoped by the user then delete the task.

int id = Convert.ToInt32(taskItem[SPBuiltInFieldId.WorkflowItemId]);
SPListItem item = list.GetItemById(id);

string workflowInstanceId = taskItem[SPBuiltInFieldId.WorkflowInstanceID].ToString();
SPWorkflow workflow = item.Workflows[new Guid(workflowInstanceId)];
If (workflow.StatusValue = SPWorkflowStatus.StoppedByUser)
{
    taskItem.Delete();
}