CComPtr CoCreateInstance returns 0x80070582 (Class already exists.)

Posted by Trevor Balcom on Stack Overflow See other posts from Stack Overflow or by Trevor Balcom
Published on 2010-05-18T16:04:57Z Indexed on 2010/05/18 17:40 UTC
Read the original article Hit count: 428

Filed under:

c++

|

atl

|

com

|

smart-pointers

I have a StartComObjects function called when the user presses the Login button and a StopComObjects function called when the user presses the Cancel button. The StartComObjects function uses CComPtr.CoCreateInstance to create the COM object and sets up some connection points using AfxConnectionAdvise. When the user presses the Cancel button the connection points are disconnected using AfxConnectionUnadvise and the COM object is stopped before calling Release on the CComPtr.

When I press the login button a second time the CComPtr.CoCreateInstance returns 0x80070582 (Class already exists). This prevents the COM object from being created on the second call to StartComObjects. I am not sure why this isn't working. Shouldn't CComPtr::Release free the COM object and allow me to create a new one after the old one was stopped? Is there any way to get around this?

© Stack Overflow or respective owner

Related posts about c++

Which C++ book shold I get between "C++ Primer" vs "C++ Primer Plus"

as seen on Stack Overflow - Search for 'Stack Overflow'
I want to learn C++ by using Vim and MinGW as compiler. I'm interesting at "C++ Primer (4th Edition)" and "C++ Primer Plus (5th Edition)" but I don't know how about it different. It has no book store that I can review those books, so I want to know, what is the different between those book and which… >>> More
C++ : C++ Primer (Stanley Lipmann) or The C++ programming language (special edition)

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a Computer Science degree (long2 time ago) .. I do know Java OOP but i am now trying to pick up C++. I do have C and of course data structure using C or pascal. I have started reading Bjarne Stroustrup book (The C++ Programming Language - Special Edition) but find it extremely difficult esp… >>> More
I need help on my C++ assignment using MS Visual C++

as seen on Stack Overflow - Search for 'Stack Overflow'
Ok, so I don't want you to do my homework for me, but I'm a little lost with this final assignment and need all the help I can get. Learning about programming is tough enough, but doing it online is next to impossible for me... Now, to get to the program, I am going to paste what I have so far. This… >>> More
Managed c++ std::string not accessible in unmanaged c++

as seen on Stack Overflow - Search for 'Stack Overflow'
In unmanaged c++ dll i have a function which takes constant std::string as argument Prototype : void read ( const std::string &imageSpec_ ) I call this function from managed c++ dll by passing a std::string. When i debug the unmanaged c++ code the parameter imageSpec_ shows the value correctly… >>> More
The Definitive C++ Book Guide and List

as seen on Stack Overflow - Search for 'Stack Overflow'
After more than a few questions about deciding on C++ books I thought we could make a better community wiki version. Providing QUALITY books and an approximate skill level. Maybe we can add a short blurb/description about each book that you have personally read / benefited from. Feel free to debate… >>> More

Related posts about atl

Delphi and Microsoft ATL security issue

as seen on Stack Overflow - Search for 'Stack Overflow'
My impression is that standard Delphi uses the Win32 API. Recently Microsoft has been communicating a problem regarding ATL that requires application developers to rebuild ATL-using applications after installing an update on their machines. Will this practice be the general case also for Delphi… >>> More
Problem hosting WebBrowser control in an ATL app.

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a legacy atl app that hosts a webbrowser control in an ATL window. I create an instance of the client to host the browser using the following sequence CComPtr<IOleObject> spOleObject; HRESULT hr = CoCreateInstance(CLSID_WebBrowser, NULL, CLSCTX_INPROC, ID_IOleObject,(void**)&spOleObject); spOleObject->SetClientSite(this); GetClientRect(&rcClient); hr… >>> More
How to use MFC with ATL

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I'm trying to write a COM EXE using ATL. I also have a MFC application. Both these applications would be run in local machines. Therefore, I don't need to run these two processes (COM EXE and MFC) separately. Can I create a single application (process) by combining these two applications ? Is… >>> More
ATL CString or_bstr_t?

as seen on Stack Overflow - Search for 'Stack Overflow'
In our COM project, we need to choose between best string class implementation so that BSTR (used for COM interfaces) and elegant string class like CString provides many string manipulation APIs. Are there any better way to handle the strings and string operations so that it can be BSTR complaints… >>> More
WM_POWERBROADCAST handler for CMainDlg in ATL app not invoked

as seen on Stack Overflow - Search for 'Stack Overflow'
I have an ATL app where I want to handle WM_POWERBROADCAST. I have a CMainDlg (CAxDialogImpl) in whose MSG_MAP I defined the handler. BEGIN_MSG_MAP(CMainDlg) ... MESSAGE_HANDLER(WM_POWERBROADCAST, OnPowerChange) ... END_MSG_MAP() However, the handler isn't invoked when I do things that… >>> More