Call to a method never returns

Question

I am working with a COM component. There is a method that does this call to the component, and this method is used many times in my application, for each document to be processed, this method is called.

One weird thing happens sometimes suddenly, doesn't matter the amount of documents processed, it can happen after processing 60, 100 or 300 documents, or just don't happen. The weird thing: the call to the component doesn't return. The method stays stuck into the call line. Do you know any COM particularity that could be causing this problem?

Answer 1

From your question I get that your are doing COM automation with documents. If your COM object is a document processing application (Would MS Office be the right guess?) then it might be that the application is simply blocked by a popup.

This phenomenon happens quite frequently when you automate e.g. Word or Excel. You should do several things to work around this problem (I'm talking about MS Word here):

• disable alerts by setting Application.DisplayAlerts accordingly
• install the complete products to avoid Windows Installer popups asking for missing features
• implement a time-out mechanism that will kill the application if any modal dialog is requesting user input. The reason for that is that there are certain types of popups which cannot be suppressed (If you need further information please ask).