C / C++ / MFC
|<b>In process / progress of being solved</b>
WM_DEVICECHANGE sets wParam to DBT_DEVNODES_CHANGED to update list (tree?) nodes.
No other info is available then. I have not retrieved any device list, so it is useless for me.
To receive DBT_DEVICEARRIVAL it is necessary to first use RegisterDeviceNotification.
At this point no other help is required.
I need some help / hints with implementing WM_DEVICECHANGE in MFC Document /View setup.
I have managed to intercept the WM_DEVICECHANGE in CmainFrame message map and process it .
The problem m is that the wParam is nowhere near the 0x8xxx, but it is plain “7” and the lParam is 0.
I went thru the Dbt.h and cannot figure out what is the wParam = 7 telling me.
Here is the code snippet and if it is not formatted to you liking – I am sorry , but I write my stuff in OpenOffice and than copy it to CodeProject so it cannot be formatted properly.
<b>I just need some troubleshooting pointer / suggestion how to analyze these mysterious parameters. </b>
Maybe CmainFRame is not the place to start, but I got same parameters values when I used Cdialog message map directly.
Any help is as always appreciated.
bool CMainFrame::OnMyDeviceChange(WPARAM wParam, LPARAM lParam)
TRACE("\nLRESULT CMainFrame::OnMyDeviceChange(WPARAM wParam, LPARAM lParam)");
TRACE("\nwparam %i ",wParam);
TRACE("\nlParam %i ",lParam);
AfxMessageBox("!!!! CMainFrame::Device detection ");
// pass WM_HARDWARE to view
JUst found this info, so the additional question is - is CMainFrame "top window" and if not will RegisterDeviceNotification solve this ? I shall try it next.
The DBT_DEVICEARRIVAL and DBT_DEVICEREMOVECOMPLETE events are automatically broadcast to all top-level windows for port devices. Therefore, it is not necessary to call RegisterDeviceNotification for ports, and the function fails if the dbch_devicetype member is DBT_DEVTYP_PORT.
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