ListView Assert - IsWindow(m_hWnd)

[Shutter]

Hi, I have a listview as one of my splitter panes. A function in this view is as follows: void MyFunction(CString* str) { // Code to insert str as an item // such as GetListBox().InsertItem(0,str); // The same thing happens no matter what method I try... // but the view isn't recognized as a window. } But whenever I try to do so, it asserts saying that it isn't a window. A listview works just fine in another 2 applications I have a listview in. Everything is standard...I haven't overridden any functions. The documentation says I don't need to create a ListCtrl because the view did. Any suggestions? :confused: Shutter

[Beer]

this may sound awkward, but did you try passing the CString by value instead? I've had some nasty stuff happen when I tried passing CStrings by a pointer then using them in controls. hey

[Shutter]

That was a typo there...actually, I'm just using a CString instead of a CString*... I did try your code, but unfortunately it didn't work either. I've tried many functions... they all assert. It seems to think that there isn't a window there. Perhaps it's a cast of some sort that I'm missing...I really have no idea. Shutter

[valikac]

Add a member variable to the main frame that corresponds to the listview. Kuphryn

[Shutter]

Could you expand on that? Shutter

[valikac]

In your code you get a pointer to the listview via GetListBox(). I meant you could assign a member variable to the listview instead of GetListBox(). Kuphryn

[Baris Kurtlutepe]

There's also the possibility that if you call this function from a thread that is not the creator of the listview control, this assert will fire (something like ASSERT(IsWindow(..))). Is this the case?

[Shutter]

I haven't involved separate threads in the application. I've tried creating a ListCtrl in a formview, tried adding a ListCtrl into a CView, tried using a CListView... but still no luck. The thing is, I can see the header when I have it in Report mode, and Spy++ picks up on the windows messages for it. But even calling IsWindow on it returns false. What gets me is it's a CListView with no modification whatsoever. Oh well, I'll try more in the morning. Shutter

[JT Anderson]

What is the value of m_hWnd at the time you get the ASSERT failure? Is it NULL? You haven't created the window. Is it 0xDDDDDDDD? You have deleted the CListView object. Is it 0xCDCDCDCD? I don't know how this could be. But it is interesting. (It would mean m_hWnd had not be initialized.) If it is something else, what is it? -------- There are 10 types of people in this world. Those who know binary and those who don't.

[Shutter]

It comes back null. But isn't the ListView supposed to create it?

[JT Anderson]

Nothing happens by magic. Sometimes the framework creates windows for you. Sometimes you need to create them yourself. In this case it appears you need to create the window yourself. You have the MFC source. Read it. Debug it. Learn it. -------- There are 10 types of people in this world. Those who know binary and those who don't.