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The new project wizard can create an MFC project that behaves like the Windows File Explorer. The navigation pane that allows the user to navigate through the file system is based on an MFC class called CTreeView which hosts a CTreeCtrl. The class wizard allows the user to create a message handler for the TVN_SELCHANGED message. When the user changes the selection in the navigation pane, the handler is not being called.
I have duplicated the issue in VS2015, VS2017, and VS2019. Is this a bug or am I not understanding how to use the CTreeView class?
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Hi, @semicode •
navigation pane is CMFCShellTreeCtrl.
Generated by project wizard: VS 2022
You need to create MFC class that inherits from CMFCShellTreeCtrl.
And add TVN_SELCHANGED from class wizard.
Then replace the CMFCShellTreeCtrl m_wndTree (MainFrm.h) with Your class m_wndTree;
Best regards,
Minxin Yu
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Thanks for the response @Minxin Yu
I will give your suggestions a try.
That does not change the fact that the project wizard is creating code that does not work however. This is a screen shot of the application that was created by three different versions of Visual Studio:
The navigation pane created is a class called CLeftView as follows:
class CLeftView : public CTreeView
It is this class that I added the message handler to:
I need the navigation pane to work for my application and I am anxious to give your suggestion a try.
Hopefully Microsoft will fix the new project wizard to generate code that works so that developers do not spend hours trying to make the code the wizard generates functional.
Thanks for the response @Minxin Yu
I am a little slow, but this time you got through😏.
After making the changes you suggested, deriving a class from CMFCShellTreeCtrl:
I then replaced the CMFCShellTreeCtrl with CNavigator in the main frame window and using the Class Wizard:
I added the selection change message handler to the new CNavigator class.
I verified everything worked by setting a break point in the handler.
Thank you for your help and persistence.
Best regards,
The issue you're experiencing with the CTreeView class not receiving the TVN_SELCHANGED message when clicking in the navigation pane could be due to how the selection change notifications are handled. The CTreeCtrl sends TVN_SELCHANGING and TVN_SELCHANGED notifications when the selection changes, but if the selection is not being detected, it may be related to the way the message handlers are set up or how the tree control is configured.
Ensure that your message handler for TVN_SELCHANGED is correctly implemented and that the control is properly set to receive these notifications. If the handler is not being called, double-check that the control is correctly associated with the message map and that the notifications are not being filtered out or overridden by other handlers.
If you've confirmed that everything is set up correctly and the issue persists across multiple versions of Visual Studio, it may be worth investigating if there are any known issues or bugs related to CTreeView in those specific versions.
References: