Open and Close CD/DVD Drive Tray

Introduction

This tip shows you how to open and close the CD or DVD drive tray programmatically.

Background

There are tools that allow you to do this (like NirSoft's NirCmd), but I wrote this out of curiosity, to find out how it is done. The close command is particularly useful, since Windows doesn't provide that feature.

Disclaimer

This is merely one method of controlling the drive tray, and may not work in all instances. I am sure there are other methods too.

Code

We use the Media Control Interface (MCI) function mciSendCommand to open and close the tray. Specifying MCI_SET_DOOR_OPEN ejects the tray, and MCI_SET_DOOR_CLOSED retracts it. Example:

mciSendCommand(deviceId, MCI_SET, MCI_SET_DOOR_CLOSED, NULL);

Refer to the MSDN documentation for details of mciSendCommand and its arguments.

Demo Program

The following demo opens and closes the CD drive door. The drive letter is hardcoded for simplicity.

#include <tchar.h>
#include <windows.h>
#include <mmsystem.h> // for MCI functions

// Link to winmm.lib (usually included in project settings)
#pragma comment(lib, "winmm")

void ControlCdTray(TCHAR drive, DWORD command)
{
	// Not used here, only for debug
	MCIERROR mciError = 0;

	// Flags for MCI command
	DWORD mciFlags = MCI_WAIT | MCI_OPEN_SHAREABLE | 
		MCI_OPEN_TYPE | MCI_OPEN_TYPE_ID | MCI_OPEN_ELEMENT;

	// Open drive device and get device ID
	TCHAR elementName[] = { drive };
	MCI_OPEN_PARMS mciOpenParms = { 0 };
	mciOpenParms.lpstrDeviceType = (LPCTSTR)MCI_DEVTYPE_CD_AUDIO;
	mciOpenParms.lpstrElementName = elementName;	
	mciError = mciSendCommand(0, 
		MCI_OPEN, mciFlags, (DWORD_PTR)&mciOpenParms);

	// Eject or close tray using device ID
	MCI_SET_PARMS mciSetParms = { 0 };
	mciFlags = MCI_WAIT | command; // command is sent by caller
	mciError = mciSendCommand(mciOpenParms.wDeviceID, 
		MCI_SET, mciFlags, (DWORD_PTR)&mciSetParms);
	
	// Close device ID
	mciFlags = MCI_WAIT;
	MCI_GENERIC_PARMS mciGenericParms = { 0 };
	mciError = mciSendCommand(mciOpenParms.wDeviceID, 
		MCI_CLOSE, mciFlags, (DWORD_PTR)&mciGenericParms);
}

// Eject drive tray
void EjectCdTray(TCHAR drive)
{
	ControlCdTray(drive, MCI_SET_DOOR_OPEN);
}

// Retract drive tray
void CloseCdTray(TCHAR drive)
{
	ControlCdTray(drive, MCI_SET_DOOR_CLOSED);
}

int _tmain(int argc, _TCHAR* argv[])
{
	EjectCdTray(TEXT('E')); // drive letter hardcoded
	CloseCdTray(TEXT('E'));

	return 0;
}

Conclusion

That's it. Let me know if you discover any bugs.