To change the drive letter without restarting machine

[ajitm]

Hi!
I have written code to change name of the drive, for example drive 'D' to drive 'E' it runs successfully but to reflect the changes i need to restart my machine. So please provide any solution which will cause to reflect the changes without restarting my machine. I have made necessary changes in the registry by code but these changes are not reflected immediately for that i have to restart my machine plz if any suggestion.

Thanks in advance.

[Computergeek01]

If by any solution you mean to include non C++ solutions then this is three lines of code in VBS:

Set objNetwork = CreateObject("WScript.Network")
objNetwork.RemoveNetworkDrive "E:"
objNetwork.MapNetworkDrive "F:" , "\\Server\Folder"

"E:" and "F:" Being the drive letters of your choice of course.

For simple things like this VBS is better suited, however if this is part of a larger program please say so and I will help you further.

EDIT: Doing this does NOT require a restart.

[ajitm]

Thanks for your reply.

But when I am trying to rename drive letter from the computer management it works fine and we don't have to restart the machine. so i just want to know which are the windows API's are calling while renaming the drive letter. I need a solution which is totally part of C++.

Thanks in advance.

[kbw]

What does your code do, rename registry entries?

[ajitm]

please refer the fallowing code for changing drive name 'E' to 'D'



#include "stdafx.h"
#include<windows.h>
#include<stdio.h>
#include<iostream>
#include<atlstr.h>
using namespace std;
int _tmain(int argc, _TCHAR* argv[])
{
CString newstr,oldstr;
long result;
HKEY hkey;
DWORD Type = REG_BINARY;
DWORD cbData;
char ch;

//Select the name of the drive to change.
ch=(char)'E';
oldstr.Format(L"%c",ch);

//Select the new name of the drive.
ch=(char)'D';
newstr.Format(L"%c",ch);

oldstr="\\DosDevices\\"+oldstr;
newstr="\\DosDevices\\"+newstr;
oldstr=oldstr +':';
newstr=newstr +':';

//Open the specified registry key.
result=RegOpenKeyEx(HKEY_LOCAL_MACHINE,L"System\\MountedDevices",0,
KEY_ALL_ACCESS|KEY_WRITE|KEY_SET_VALUE,&hkey);


result = RegQueryValueEx(hkey,oldstr.GetBuffer(oldstr.GetLength()),
NULL,&Type,NULL,&cbData);

LPBYTE dat;
dat = (LPBYTE) malloc( cbData );

cbData = cbData + 1;
result = RegQueryValueEx(hkey,oldstr.GetBuffer(oldstr.GetLength()),
NULL,&Type,dat,&cbData);

if(result!=ERROR_SUCCESS)
{
MessageBox(NULL,L"Failed to Query value",L"Error", MB_OK | MB_ICONERROR );
return 0;
}

// Set new value into the registry.
result = RegSetValueEx(hkey,newstr.GetBuffer(newstr.GetLength()),NULL,Type,dat,cbData);
if(result!=ERROR_SUCCESS)
{
MessageBox(NULL,L"Failed to set the value in Registry",L"Error", MB_OK | MB_ICONERROR );
return 0;
}

// Now the old drive name is deleted in the registry

result = RegDeleteValue(hkey,oldstr.GetBuffer(oldstr.GetLength()));
if(result!=ERROR_SUCCESS)
{
MessageBox(NULL,L"Failed in deleting the Value",L"Error", MB_OK | MB_ICONERROR );
return 0;
}

RegCloseKey(hkey);

return 0;
}


After execution of this code i will get corresponding changes in registry but those changes are not reflected in the explorer. For that i have to restart the system which i won't.

[kbw]

Yeah, that's changing registry entries.

You'll probably find the applet is going straight to the device driver in an undocumented way. Whatever that is, it's not an API call.

[ajitm]

ya the program is changing only registry entries, but i want those changes reflected on the explorer means drive letter are getting changed but not shown in the explorer for that i have to restart the system. So plz tell me the further solution as i am beginner.

Thanks for your response.

[ajitm]

Hi,

As we can change drive letter from control panel --> computer management --> Disk management by right click on volume header. same thing I want to do using c++. I am succeed for making changes in the registry but those are not reflecting in the explorer for that I have restart my system which I won't. I think as we can successfully change the drive letter using computer management we can have those changes using programming also. As I am new to this area please provide any solution regarding this. What is happening while making changes through computer management or what are API's are called or If I am doing completely wrong then also you can suggest me for the correct way.

Your help is really appreciable.

[Null]

Here you go:

#define _WIN32_WINNT 0x500 

#include <iostream>
#include <windows.h>
using namespace std;

int main()
{
char *old_mountpoint="H:\\",
     *new_mountpoint="G:\\";
     
char unc_path[512]; // UNC path is needed to mount a device

GetVolumeNameForVolumeMountPoint(old_mountpoint,unc_path,512); // Get the UNC path of the volume
clog <<"UNC path of the disk: "<<unc_path<<endl;

DeleteVolumeMountPoint(old_mountpoint);

SetVolumeMountPoint(new_mountpoint,unc_path);

}

GetVolumeNameForVolumeMountPoint http://msdn.microsoft.com/en-us/library/aa364994(v=vs.85).aspx
DeleteVolumeMountPoint: http://msdn.microsoft.com/en-us/library/aa363927(v=vs.85).aspx
SetVolumeMountPoint: http://msdn.microsoft.com/en-us/library/aa365561(v=vs.85).aspx

EDIT: added #define _WIN32_WINNT 0x500

[ajitm]

The function in the above code return error 123 I think the path specified in old_mountpoint parameter is wrong i have also tried path as \\.\\H:\\ but it is not working.

[ajitm]

Thanks to everyone for your valuable time.