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Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here.


The framework calls this member function to notify an application or device driver of a change to the hardware configuration of a device or the computer.

afx_msg BOOL OnDeviceChange( 
   UINT nEventType, 
   DWORD_PTR dwData  


An event type. See the Remarks section for a description of the available values


The address of a structure that contains event-specific data. Its meaning depends on the given event.

For devices that offer software-controllable features, such as ejection and locking, the operating system typically sends a DBT_DEVICEREMOVEPENDING message to let applications and device drivers end their use of the device gracefully.

If the operating system forcefully removes of a device, it may not send a DBT_DEVICEQUERYREMOVE message before doing so.

The nEvent parameter can be one of these values:


This member function is called by the framework to allow your application to handle a Windows message. The parameters passed to your function reflect the parameters received by the framework when the message was received. If you call the base-class implementation of this function, that implementation will use the parameters originally passed with the message and not the parameters you supply to the function.

Header: afxwin.h

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