DTE2 events don't fire

Question

While trying to develop my first VS Addin, I am having issues in firing DTE2 events.

Basically, the DocumentOpened and LineChanged events don't fire for some reason. What important part did I miss?

namespace TestAddin {
  public class Connect : IDTExtensibility2 {
    private AddIn _addInInstance;
    private DTE2 _applicationObject;

    public void OnConnection(object application, ext_ConnectMode connectMode, object addInInst, ref Array custom) {
      _applicationObject = (DTE2) application;
      _addInInstance = (AddIn) addInInst;

      _applicationObject.Events.DocumentEvents.DocumentOpened += InitializeFoldingOnDocument;
      _applicationObject.Events.TextEditorEvents.LineChanged += UpdateFoldingOnDocument;
    }

    private void UpdateFoldingOnDocument(TextPoint startpoint, TextPoint endpoint, int hint) {
      RegionFolding(_applicationObject.ActiveDocument);
    }

    private void InitializeFoldingOnDocument(Document document) {
      RegionFolding(document);
    }

    private void RegionFolding(Document _document) {
      // Do the folding [...]
    }

    // Other IDTExtensibility2 Members [...]
  }
}

Answer 1

You need to save the DocumentEvents class. I think they will be desposed or garbage collected else.

In my case.

private SolutionEvents solutionEvents;

public void OnConnection(object application, ext_ConnectMode connectMode, object addInInst, ref Array custom)
{
    Globals.DTE = (DTE2)application;
    Globals.Addin = (AddIn)addInInst;

    solutionEvents = Globals.DTE.Events.SolutionEvents;
    solutionEvents.Opened += new _dispSolutionEvents_OpenedEventHandler(SolutionEvents_Opened);
    solutionEvents.BeforeClosing += new _dispSolutionEvents_BeforeClosingEventHandler(SolutionEvents_BeforeClosing);
}

Answer 2

I found a different solution to this problem.

I was boxing and unboxing my DTE object before doing my event subscriptions. This ulitmately proved the culprit for me. While this wasn't your issue, it could help others who have similar issues; and is good to know so that you don't make the same mistakes I did which took an extreme amount of time to resolve.

See here: http://social.msdn.microsoft.com/Forums/en-US/vsx/thread/eb1e8fd1-32ad-498c-98e9-25ee3da71004