Wouldn't using the string parameter to externalObject.Item as the key solve your problem? You would not store the Item value (a reference to a .NET object wrapping the COM item) in the hash table at all. As you've discovered, the usefulness of that value is limited due to different threads having different .NET wrappers for the same COM object.
During a callback, get the "name" (or whatever the .Item parameter string is called) from the passed-in Item and use that to retrieve your app's associated info from the HashTable. (Any info about the Item that you need -- that your app doesn't store -- could be retrieved from the passed-in Item.) Do you really need to hold on to the Item reference value for some reason? (I don't know what that would be, since the value can't be used by both threads.) If you do, you could possibly record _both_ the child thread's Item value and the GUI thread's Item value in your app's data. Whether it was the child thread or the GUI thread that first saw the particular Item, it would record its thread-specific Item value in "its" slot and leave the other (default NULL) alone. But I don't really think you'd ever need this. Of course, you might have confused me by using "MyItem" as the .Item parameter, when perhaps it's something that could change and thus can't be used as the HashTable key on the .NET side (ugh). At 05:03 PM 9/12/2003 +0400, Dmitry Shaporenkov wrote >----- Original Message ----- >From: "Ron O'Rourke" <[EMAIL PROTECTED]> >To: <[EMAIL PROTECTED]> >Sent: Friday, September 12, 2003 4:24 PM >Subject: Re: [ADVANCED-DOTNET] Object identities, marshaling issues and >interoperability > >> Assuming you have the ability to modify the Item code [snip] > > I can't change Item implementation. Well, when I was talking about some >information > in the Hashtable, this information was really a wrapper around Items, >and the Hashtable contains > mapping from Items to corresponding wrappers. Even having Items wrapped, >I still sometimes need > to get the wrapper for an Item. In particular, this happens when the UI >thread receives an event from the > external component and the event contains an Item as an argument. The UI >thread hence accesses the hashtable > to get the wrapper, and the problem arises. > >> >> On Fri, 12 Sep 2003 13:25:27 +0400, Dmitry Shaporenkov wrote: >> >> >Hi all, >> >> <Snip> >> >> >However, I need a way to identify items in a thread-independent fashion. >> >Items themselves do not have any properties which might serve as a >reliable >> >unique identifiers. >> >> <Snip> >> >> >Any advices / references will be greatly appreciated. Thanks in advance. >> > >> >Regards, >> >Dmitry Shaporenkov J. Merrill / Analytical Software Corp =================================== This list is hosted by DevelopMentorŪ http://www.develop.com NEW! ASP.NET courses you may be interested in: 2 Days of ASP.NET, 29 Sept 2003, in Redmond http://www.develop.com/courses/2daspdotnet Guerrilla ASP.NET, 13 Oct 2003, in Boston http://www.develop.com/courses/gaspdotnet View archives and manage your subscription(s) at http://discuss.develop.com
