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How can I detect cdrom/usb device insertions?

P: n/a
I am writing a C# app that needs to periodically poll for cdroms and usb
storage device insertions. I've looked at the WMI functions but haven't
found anything all that useful. The closest is Win32_DiskDrive, but it
doesn't seem to return any information on cdrom devices. I suspect there
might be a Win32 API call, but I haven't found any info yet using Google. Is
there a way to achieve this in C#?

Nov 16 '05 #1
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9 Replies


P: n/a
Paul,

Have a look at this CodeProject article:
http://www.codeproject.com/dotnet/de...umemonitor.asp

Alexander

"Paul Steele" <pa*********@acadiau.ca> wrote in message
news:uA**************@TK2MSFTNGP12.phx.gbl...
I am writing a C# app that needs to periodically poll for cdroms and usb
storage device insertions. I've looked at the WMI functions but haven't
found anything all that useful. The closest is Win32_DiskDrive, but it
doesn't seem to return any information on cdrom devices. I suspect there
might be a Win32 API call, but I haven't found any info yet using Google.
Is there a way to achieve this in C#?

Nov 16 '05 #2

P: n/a
Hi,
I'm not sure whether you can do it in C#, i.e you have any direct classes
for this, but you have Win32 API's for detecting the cdroms insertions. The
following data may be helpful to you. Courtesy, MSDN

Detecting Media Insertion or Removal
Windows sends all top-level windows a set of default WM_DEVICECHANGE
messages when new devices or media (such as a CD or DVD) are added and become
available, and when existing devices or media are removed. You do not need to
register to receive these default messages. See the Remarks section in
RegisterDeviceNotification for details on which messages are sent by default.
The messages in the code example below are among the default messages.

Each WM_DEVICECHANGE message has an associated event that describes the
change, and a structure that provides detailed information about the change.
The structure consists of an event-independent header, DEV_BROADCAST_HDR,
followed by event-dependent members. The event-dependent members describe the
device to which the event applies. To use this structure, applications must
first determine the event type and the device type. Then, they can use the
correct structure to take appropriate action.
When the user inserts a new CD or DVD into a drive, applications receive a
WM_DEVICECHANGE message with a DBT_DEVICEARRIVAL event. The application must
check the event to ensure that the type of device arriving is a volume (the
dbch_devicetype member is DBT_DEVTYP_VOLUME) and that the change affects the
media (the dbcv_flags member is DBTF_MEDIA).

When the user removes a CD or DVD from a drive, applications receive a
WM_DEVICECHANGE message with a DBT_DEVICEREMOVECOMPLETE event. Again, the
application must check the event to ensure that the device being removed is a
volume and that the change affects the media.

The following code demonstrates how to check for insertion or removal of a
CD or DVD.
#include <windows.h>
#include <dbt.h>

void Main_OnDeviceChange (HWND hwnd, WPARAM wParam, LPARAM lParam);
char FirstDriveFromMask (ULONG unitmask); //prototype

/*------------------------------------------------------------------
Main_OnDeviceChange (hwnd, wParam, lParam)

Description
Handles WM_DEVICECHANGE messages sent to the application's
top-level window.
--------------------------------------------------------------------*/

void Main_OnDeviceChange (HWND hwnd, WPARAM wParam, LPARAM lParam)
{
PDEV_BROADCAST_HDR lpdb = (PDEV_BROADCAST_HDR)lParam;
char szMsg[80];

switch(wParam)
{
case DBT_DEVICEARRIVAL:
// Check whether a CD or DVD was inserted into a drive.
if (lpdb -> dbch_devicetype == DBT_DEVTYP_VOLUME)
{
PDEV_BROADCAST_VOLUME lpdbv = (PDEV_BROADCAST_VOLUME)lpdb;

if (lpdbv -> dbcv_flags & DBTF_MEDIA)
{
wsprintf (szMsg, "Drive %c: Media has arrived.\n",
FirstDriveFromMask(lpdbv ->dbcv_unitmask));

MessageBox (hwnd, szMsg, "WM_DEVICECHANGE", MB_OK);
}
}
break;

case DBT_DEVICEREMOVECOMPLETE:
// Check whether a CD or DVD was removed from a drive.
if (lpdb -> dbch_devicetype == DBT_DEVTYP_VOLUME)
{
PDEV_BROADCAST_VOLUME lpdbv = (PDEV_BROADCAST_VOLUME)lpdb;

if (lpdbv -> dbcv_flags & DBTF_MEDIA)
{
wsprintf (szMsg, "Drive %c: Media was removed.\n",
FirstDriveFromMask(lpdbv ->dbcv_unitmask));

MessageBox (hwnd, szMsg, "WM_DEVICECHANGE", MB_OK);
}
}
break;

default:
/*
Process other WM_DEVICECHANGE notifications for other
devices or reasons.
*/
;
}
}

/*------------------------------------------------------------------
FirstDriveFromMask (unitmask)

Description
Finds the first valid drive letter from a mask of drive letters.
The mask must be in the format bit 0 = A, bit 1 = B, bit 3 = C,
etc. A valid drive letter is defined when the corresponding bit
is set to 1.

Returns the first drive letter that was found.
--------------------------------------------------------------------*/

char FirstDriveFromMask (ULONG unitmask)
{
char i;

for (i = 0; i < 26; ++i)
{
if (unitmask & 0x1)
break;
unitmask = unitmask >> 1;
}

return (i + 'A');
}

Pradeep Kumar.R

"Paul Steele" wrote:
I am writing a C# app that needs to periodically poll for cdroms and usb
storage device insertions. I've looked at the WMI functions but haven't
found anything all that useful. The closest is Win32_DiskDrive, but it
doesn't seem to return any information on cdrom devices. I suspect there
might be a Win32 API call, but I haven't found any info yet using Google. Is
there a way to achieve this in C#?

Nov 16 '05 #3

P: n/a
This is definitely a good starting point. Unfortunately it does not detect
USB key insertions...

"Alexander Shirshov" <al*******@omnitalented.com> wrote in message
news:ef**************@TK2MSFTNGP09.phx.gbl...
Paul,

Have a look at this CodeProject article:
http://www.codeproject.com/dotnet/de...umemonitor.asp

Alexander

"Paul Steele" <pa*********@acadiau.ca> wrote in message
news:uA**************@TK2MSFTNGP12.phx.gbl...
I am writing a C# app that needs to periodically poll for cdroms and usb
storage device insertions. I've looked at the WMI functions but haven't
found anything all that useful. The closest is Win32_DiskDrive, but it
doesn't seem to return any information on cdrom devices. I suspect there
might be a Win32 API call, but I haven't found any info yet using Google.
Is there a way to achieve this in C#?


Nov 16 '05 #4

P: n/a
Read the comments at the bottom.

"Paul Steele" <pa*********@acadiau.ca> wrote in message
news:en****************@TK2MSFTNGP10.phx.gbl...
This is definitely a good starting point. Unfortunately it does not detect
USB key insertions...


Nov 16 '05 #5

P: n/a
I presume you are referring to the comment:

"The first one is dbcv_flags. This field will tell us the nature of the
volume that was mounted (or dismounted). It can be either a media volume
like a CD (the flag will have a DBTF_MEDIA flag) or a network share
(DBTF_NET). In this case we will only be interested in filtering the
DBTF_MEDIA value. The other field is dbcv_unitmask, which is a bit vector
that tells us which drive letters were mounted."

If I remove the check for DBTF_MEDIA in the code, then it does detect USB
keys. Unfortunately it also detects network share mounts. There doesn't seem
to be a differentiation between a USB Key and network media. Am I
overlooking something?

"Alexander Shirshov" <al*******@omnitalented.com> wrote in message
news:e9**************@TK2MSFTNGP09.phx.gbl...
Read the comments at the bottom.

"Paul Steele" <pa*********@acadiau.ca> wrote in message
news:en****************@TK2MSFTNGP10.phx.gbl...
This is definitely a good starting point. Unfortunately it does not
detect USB key insertions...

Nov 16 '05 #6

P: n/a

"Paul Steele" <pa*********@acadiau.ca> wrote in message
news:uA**************@TK2MSFTNGP12.phx.gbl...
I am writing a C# app that needs to periodically poll for cdroms and usb
storage device insertions. I've looked at the WMI functions but haven't
found anything all that useful. The closest is Win32_DiskDrive, but it
doesn't seem to return any information on cdrom devices. I suspect there
might be a Win32 API call, but I haven't found any info yet using Google.
Is there a way to achieve this in C#?


Use 'Win32_LogicalDisk' instead of Win32_DiskDrive and register a
asynchronous event handler for __InstanceModificationEvent, something like
this will do.

using System.Management;
class TestClass{
public static void Main() {
TestClasswe = new TestClass();
ManagementEventWatcher w= null;
WqlEventQuery q = new WqlEventQuery();
ManagementScope scope = new ManagementScope("root\\CIMV2");
try {
q.EventClassName = "__InstanceModificationEvent";
q.WithinInterval = new TimeSpan(0,0,3);
// DriveType - 5: CDROM
q.Condition = @"TargetInstance ISA 'Win32_LogicalDisk' and
TargetInstance.DriveType = 5 and TargetInstance.VolumeName != null";
w = new ManagementEventWatcher(scope, q);
// register async. event handler
w.EventArrived += new EventArrivedEventHandler(we.CDREventArrived);
w.Start();
// Do something usefull,block thread for testing
Console.ReadLine();
}
catch(Exception e) {
Console.WriteLine(e.Message);
}
finally {
w.Stop();
}
}
// Dump some properties
public void CDREventArrived(object sender, EventArrivedEventArgs e) {
//Get the Event object and display it
PropertyData pd;
if(( pd = e.NewEvent.Properties["TargetInstance"]) != null)
{
ManagementBaseObject mbo = pd.Value as ManagementBaseObject;
Console.WriteLine(mbo.Properties["VolumeName"].Value);
}

Willy.
Nov 16 '05 #7

P: n/a
I put in your code more or less as given but the event never fires. I'm not
familiar with ManagementEventWatcher, which makes the code somewhat vague,
although I get the general idea behind it. Is there something I can do to
test it?

"Willy Denoyette [MVP]" <wi*************@pandora.be> wrote in message
news:uY**************@TK2MSFTNGP09.phx.gbl...

"Paul Steele" <pa*********@acadiau.ca> wrote in message
news:uA**************@TK2MSFTNGP12.phx.gbl...
I am writing a C# app that needs to periodically poll for cdroms and usb
storage device insertions. I've looked at the WMI functions but haven't
found anything all that useful. The closest is Win32_DiskDrive, but it
doesn't seem to return any information on cdrom devices. I suspect there
might be a Win32 API call, but I haven't found any info yet using Google.
Is there a way to achieve this in C#?


Use 'Win32_LogicalDisk' instead of Win32_DiskDrive and register a
asynchronous event handler for __InstanceModificationEvent, something like
this will do.

using System.Management;
class TestClass{
public static void Main() {
TestClasswe = new TestClass();
ManagementEventWatcher w= null;
WqlEventQuery q = new WqlEventQuery();
ManagementScope scope = new ManagementScope("root\\CIMV2");
try {
q.EventClassName = "__InstanceModificationEvent";
q.WithinInterval = new TimeSpan(0,0,3);
// DriveType - 5: CDROM
q.Condition = @"TargetInstance ISA 'Win32_LogicalDisk' and
TargetInstance.DriveType = 5 and TargetInstance.VolumeName != null";
w = new ManagementEventWatcher(scope, q);
// register async. event handler
w.EventArrived += new EventArrivedEventHandler(we.CDREventArrived);
w.Start();
// Do something usefull,block thread for testing
Console.ReadLine();
}
catch(Exception e) {
Console.WriteLine(e.Message);
}
finally {
w.Stop();
}
}
// Dump some properties
public void CDREventArrived(object sender, EventArrivedEventArgs e) {
//Get the Event object and display it
PropertyData pd;
if(( pd = e.NewEvent.Properties["TargetInstance"]) != null)
{
ManagementBaseObject mbo = pd.Value as ManagementBaseObject;
Console.WriteLine(mbo.Properties["VolumeName"].Value);
}

Willy.

Nov 16 '05 #8

P: n/a

"Paul Steele" <pa*********@acadiau.ca> wrote in message
news:eh**************@tk2msftngp13.phx.gbl...

"Willy Denoyette [MVP]" <wi*************@pandora.be> wrote in message
news:OG**************@TK2MSFTNGP12.phx.gbl...

"Paul Steele" <pa*********@acadiau.ca> wrote in message
news:O4**************@TK2MSFTNGP14.phx.gbl...
I put in your code more or less as given but the event never fires. I'm
not familiar with ManagementEventWatcher, which makes the code somewhat
vague, although I get the general idea behind it. Is there something I
can do to test it?


Change the query string into:
q.Condition = @"TargetInstance ISA 'Win32_LogicalDisk' and
TargetInstance.DriveType = 5";
, and insert and/or remove the CD into/from the drive.
With this change all modifications to to 'Win32_LogicalDisk' will fire
an event, while the original query will only fire when a named volume is
inserted.


Found the problem. I didn't notice that "finally" clause in the try/catch
was executing. I has removed the readline because I moved to code to a
button. Stupid mistake and the program does seem to work. There is one
weird side effect. On my desktop a floppy seek occurs every 3 seconds,
probably because the event requires the OS to query all logical devices,
including the floppy. It's too bad it can't make a silent check for the
floppy...


You can prevent this by including the DeviceId in the query.

q.Condition = @"TargetInstance ISA 'Win32_LogicalDisk' and
TargetInstance.DriveType = 5 and TargetInstance.DeviceId='E:'" // where E:
is the drive letter of the CD drive

Willy.


Nov 16 '05 #9

P: 1
rhr
Willy,
Great work, it works perfect in console app.

However do you have any idea as to why your code is not working in a Windows app?
Also after using it in console app, my A: drive keeps checking for a floppy almost every 5 secs. Do you know what is causing that? In Windows Task Manager I have a CDDetector.cshost.exe that I am not able to end the process of, do you think this is what causing the A: drive issue?

Great job though:)

Thanks.
May 4 '06 #10

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