Catch opened word file event - events

Question

I want to make an application as a word add-in that changes files when they are opened.
So I created a word add-in project in visual Studio, and this is basically the code I have :
namespace WordAddIn1
{
public partial class ThisAddIn
{
private void Application_DocumentOpen(Microsoft.Office.Interop.Word.Document Doc)
{
MessageBox.Show("doc opened");
// do my stuff
}
#region VSTO generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InternalStartup()
{
this.Application.DocumentOpen += new Word.ApplicationEvents4_DocumentOpenEventHandler(Application_DocumentOpen);
}
#endregion
}
}
The problem is, this works well if you start an empty word application (double click word.exe), then open a document, but not if the word application is started together with the document opening (double click a .doc file).

Answer 1

The DocumentOpen won't fire if you open Word by double-clicking on a document.
To Work around this you can check if a document was opened in Word and if so pass the document to Application_DocumentOpen method.
BTW - You seem to have changed the code in the InternalStartup method. As indicated by the comments you should not do this, but instead uses the ThisAddIn_Startup.

Answer 2

Here's code to do what Abbey suggested:
private void ThisAddIn_Startup(object sender, System.EventArgs a)
{
try
{
Word.Document doc = this.Application.ActiveDocument;
if (String.IsNullOrWhiteSpace(doc.Path))
{
logger.Debug(String.Format("Word initialized with new document: {0}.", doc.FullName));
ProcessNewDocument(doc);
}
else
{
logger.Debug(String.Format("Word initialized with existing document: {0}.", doc.FullName));
ProcessOpenedDocument(doc);
}
}
catch (COMException e)
{
logger.Debug("No document loaded with word.");
}
}

Answer 3

You often will have the DocumentOpen event triggered before your AddIn is loaded and sometime before the document is actually loaded into the Word Interop API. This means that on ThisAddIn_Startup, WordApp.ActiveDocument still returns Null.
A trick is to schedule a Task (System.Func<Boolean>) in your ThisAddIn_Startup event: I use a Windows.Forms.Timer and that works quite well. On Timer.Tick, try to execute the Task. If it returns false, then try again 500ms later, and so on until it works.
My Task is:
If WordApp.ActiveDocument Is Nothing Then Return False
DoSomething()
Return True
The timer will keep trying until you have an active document, i.e. until you can do something with the document the user opened by double-click.
There are other ways to expose this same mechanism: you could for example wrap this into a WordStartup object that exposes a DocumentOpenBeforeAddInStartUp event and listen to this. You could also have a wrapper of all Document changes events and trigger your own DocumentChange event when either WordStartup.DocumentOpenBeforeAddInStartUp, WordApp.DocumentChange, WordApp.DocumentOpen or WordApp.NewDocument triggers.