c# - DeviceAttached message never comes -

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i trying develop c# application can communicate usb hid. have overriden wndproc method catches of wm_devicechange events , passes devicechange method method ondevicechange (this code borrowed jan axelson) looks this....

protected override void wndproc( ref message m )  {                 try      {          //  ondevicechange routine processes wm_devicechange messages.          if ( m.msg == devicemanagement.wm_devicechange )          {              ondevicechange( m );          }           //  let base form process message.          base.wndproc( ref m );                      }      catch ( exception ex )      {          displayexception( this.name, ex );          throw ;      }              }

for reason though, everytime plug in device, whether mouse or keyboard or device developing, hid's, value of wparam 0x7;

i checked in dbt.h , value of 0x0007 ...

#define dbt_devnodes_changed            0x0007  /*  * message = wm_devicechange  * wparam  = dbt_querychangeconfig  * lparam  = 0  *  *      sent ask if config change allowed  */....

i don't stop after first message comes in either @ messages , every 1 value 0x0007. why never seeing deviceattached or deviceremoved events?

anyone usb experience have ideas?

you need register device in order receive attached , removed. see registerdevicenotification. here great example going.


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