Programmatically Cancel a SharePoint Workflow

Question

Inside a workflow I want to handle and error such as not being able to lookup a username that I want to assign a task to. So the username doesn't exsist, I'm going to notify an administrator by email of this, log it to the workflow history and then terminate the workflow.

Question is, how do I terminate the workflow, from inside the workflow as if I was clicking the 'terminate workflow' button on the SharePoint webpage.

[Update] I've tried SPWorkflowManager.CancelWorkflow() which does indeed cancel the workflow but not immediately. What happens is the code to cancel runs but then my workflow continues on to create the next task and then goes to sleep when it hit's the next tasks onTaskChanged activity. Only once it has gone to sleep does the workflow get terminated, not when CancelWorkflow is called.

This causes the obvious problem that I don't want the next task to be created. I'm calling CancelWorkflow because I want it to cancel then and there.

Solution

There are quite a few suggestions at this MSDN Thread:

Terminating a SharePoint Workflow Programatically

Here's a blog-post that succintly contains the exact same information: Cancelling a SharePoint Workflow

Lastly, and most specifically, you need to use the static method: SPWorkflowManager.CancelWorkflow(SPWorkflow workflowInstanceToBeCancelled)

EDIT

CancelWorkflow is a static class, so I've amended the call.

Comments

[Daniel Revell]

I've tried this but it hasn't solved my problem. I've updated the main post to reflect this.

[Daniel Revell]

If anyone else tries SPWorkflowManager.CancelWorkflow() you might miss it the first time. The method is static so you want to call it on the class itself and not the workflow manager object that can be gotten from the SPSite like I tried.

[MbaiMburu]

But it works correctly when you call it correctly, right? That is, when you call it on the class itself SPWorkflowManager.CancelWorkflow(SPWorkflow workflowInstance); then it does what it is supposed to do.

[Daniel Revell]

Yea it works fine, but it doesn't cancel the workflow when you call it, but it must flag the workflow to be cancelled once it's stoped executing. Aka when it goes to sleep waiting for an event. I want it to cancel as soon as it is called

[MbaiMburu]

Can't you then toss the workflow to sleep from the catch block?

[Chris Ballance]

I've been looking for this for a while, and StackOverflow came thru for me. Thanks @DevinB