Transition workflows of a work item's states

Question

I am developing a windows app that performs some common TFS tasks using the 2010 Beta 2 API (like creating new team projects, new work items, selective build, etc. ).

In the process of editing existing work items, I should be able to automatically set the 'Reason' field's values according to state change of the WI (mimic-ing Visual Studio). (eg)- When I edit a bug, when state changes from Active to Resolved, the default Reason is 'Fixed' and similarly the default Reason='Deferred' when state goes from Active to Closed. (As defined in the work item type definition xml file. ) This transition is easy to capture and implement inside a simple event handler on the form, since the initial state will be Active when the Bug is edited for the first time.

I want to know how to implement the remaining transitions like Resolved to Closed (Reason=Fixed), Resolved to Active (Reason=Test failed/Not fixed) or Closed to Active (Reason=Reactivated/Regression).

I know there is a method called WorkItem.GetNextState(current_state,action), but this doesn't help as it requires a specific action.

What I have done so far is shown below:

void cmbBugState_SelectedIndexChanged(object sender, EventArgs e)
    {
        //private enum bugWorkFlows{"Fixed","Deferred","Duplicate","As Designed","Cannot Reproduce","Obsolete","Test Failed","Not Fixed","Reactivated","Regression"}
        string[] activeToResolvedReasons = { "Fixed", "Deferred", "Duplicate", "As Designed", "Cannot Reproduce", "Obsolete" };
        string[] resolvedToActiveReasons = { "Test Failed", "Not fixed" };
        string[] resolvedToClosedReasons = activeToResolvedReasons;
        string[] closedToActiveReasons = { "Reactivated", "Regression" };
        string[] activeToClosedReasons = activeToResolvedReasons;

        cmbBugReason.Items.AddRange(activeToResolvedReasons);
        // Set the default reason according to change of state of the work item.
        if (cmbBugState.SelectedItem.ToString() == "Resolved")
        {
            cmbBugReason.Enabled = true;
            cmbBugReason.SelectedItem = activeToResolvedReasons[0];
        }
        if (cmbBugState.SelectedItem.ToString() == "Closed")
        {
            cmbBugReason.Enabled = true;
            cmbBugReason.SelectedItem = activeToResolvedReasons[1];
        }
    }

Can anyone show how to handle these events on the form?

Thanks, Tara.