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Registry get directory owner programmatically using C#

I want to read programmatically the owner of a directory (and its subdirectories) of the windows registry using C#.
For example, assume my registry contains the directory HKEY_CURRENT_USER\Software\Microsoft which is owned by the user SYSTEM. A code example (leaving out the recursion over sub-directories of dir) how I intend to use it would be:
string dir = #"HKEY_CURRENT_USER\Software\Microsoft";
string owner = ReadRegOwner(dir); // owner is "SYSTEM"
However, I am not sure how to implement ReadRegOwner in C#. I have already found the RegistrySecurity class, but I am not sure how to use it to get the owner of a registry directory. It has the GetOwner member function, but that function requires an argument of type Type and I am not sure what to pass there.
Does anyone know how to implement this?

So, an implementation could look like:
string ReadRegOwner(string dir)
{
RegistryKey key = Registry.CurrentUser.OpenSubKey(dir, false);
RegistrySecurity rs = key.GetAccessControl();
IdentityReference owner = rs.GetOwner(typeof(System.Security.Principal.NTAccount));
return owner.ToString();
}
Example:
string dir = #"Software\Microsoft";
string owner = ReadRegOwner(dir); // Looks in HKEY_CURRENT_USER
Of course, CurrentUser could be also replaced if a different base key than HKEY_CURRENT_USER is desired.

How get the name of an unknown registry key. C#

I'm trying to get the name of a Registry Key and store it as a string.
I know the path that the key will be under.
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList\
The key is the Raw path for the recycling bin. The key under this path changes from computer to computer and can store more than one subkey containing the Recycle bin depending on how many users are on the installation. (From my understanding anyway)
My goal is to get the path of the recycling bin automatically so I don't have to dig through the registry to get it. Alternatively you can manually get this path by going to C:\$Recycle.Bin\Recycle Bin and the explorer path bar will then change to the key.
The key in my case appears as S-1-5-21-3905818072-3397350780-xxxxxxxxxx-1001

You can enumerate the sub-keys using GetSubKeyNames https://learn.microsoft.com/en-us/dotnet/api/microsoft.win32.registrykey.getsubkeynames?view=netframework-4.7.2
using (var key = Registry.LocalMachine(#"SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList"))
{
foreach (var subKeyName in key.GetSubKeyNames())
{
}
}

How to find an EXE's install location - the proper way?

I am making a software in C# and MATLAB that calls another software (CMG) to do some processing. My problem is that the address of the software I have put in my program is only correct on my personal computer and not on the customers' computers (I don't know what would be the path to CMG software on their computer).
How can I provide a general form of the address in order to make it work on every computer?
The following is the path I call from my MATLAB software:
C:\Program Files (x86)\CMG\STARS\2011.10\Win_x64\EXE\st201110.exe
As you see it is in drive C and the version is 2011.10. So if customer's version is something else and it is installed on other drives, this path makes no sense.

Method 1
The registry keys SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall provides a list of where most applications are installed:
Note: It doesn't list all EXE applications on the PC as some dont require installation.
In your case I am pretty sure that CMG STARS will be listed and you will be able to search for it by iterating over all subkeys looking at the DisplayName value and fetching the InstallLocation.
Also note that this Uninstall registry key exists in 3 places in the registry:
1. SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall inside CurrentUser
2. SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall inside LocalMachine
3. SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall in LocalMachine
Here is an class that returns the installed location of an application:
using Microsoft.Win32;
public static class InstalledApplications
{
public static string GetApplictionInstallPath(string nameOfAppToFind)
{
string installedPath;
string keyName;
// search in: CurrentUser
keyName = #"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall";
installedPath = ExistsInSubKey(Registry.CurrentUser, keyName, "DisplayName", nameOfAppToFind);
if (!string.IsNullOrEmpty(installedPath))
{
return installedPath;
}
// search in: LocalMachine_32
keyName = #"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall";
installedPath = ExistsInSubKey(Registry.LocalMachine, keyName, "DisplayName", nameOfAppToFind);
if (!string.IsNullOrEmpty(installedPath))
{
return installedPath;
}
// search in: LocalMachine_64
keyName = #"SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall";
installedPath = ExistsInSubKey(Registry.LocalMachine, keyName, "DisplayName", nameOfAppToFind);
if (!string.IsNullOrEmpty(installedPath))
{
return installedPath;
}
return string.Empty;
}
private static string ExistsInSubKey(RegistryKey root, string subKeyName, string attributeName, string nameOfAppToFind)
{
RegistryKey subkey;
string displayName;
using (RegistryKey key = root.OpenSubKey(subKeyName))
{
if (key != null)
{
foreach (string kn in key.GetSubKeyNames())
{
using (subkey = key.OpenSubKey(kn))
{
displayName = subkey.GetValue(attributeName) as string;
if (nameOfAppToFind.Equals(displayName, StringComparison.OrdinalIgnoreCase) == true)
{
return subkey.GetValue("InstallLocation") as string;
}
}
}
}
}
return string.Empty;
}
}
Here is how you call it:
string installPath = InstalledApplications.GetApplictionInstallPath(nameOfAppToFind);
To get the nameOfAppToFind you'll need to look in the registry at the DisplayName:
REF: I modified the above code from here to return the install path.
Method 2
You can also use the System Management .Net DLL to get the InstallLocation although it is heaps slower and creates "Windows Installer reconfigured the product" event log messages for every installed product on your system.
using System.Management;
ManagementObjectSearcher mos = new ManagementObjectSearcher("SELECT * FROM Win32_Product");
foreach (ManagementObject mo in mos.Get())
{
Debug.Print(mo["Name"].ToString() + "," + mo["InstallLocation"].ToString() + Environment.NewLine);
}
Getting the EXE's name
Neither of the above methods tell you the name of the executable, however it is quite easy to work out by iterating over all the files in the install path and using a technique I discuss here to look at file properties to detect the EXE with the correct File Description, eg:
private string GetFileExeNameByFileDescription(string fileDescriptionToFind, string installPath)
{
string exeName = string.Empty;
foreach (string filePath in Directory.GetFiles(installPath, "*.exe"))
{
string fileDescription = GetSpecificFileProperties(filePath, 34).Replace(Environment.NewLine, string.Empty);
if (fileDescription == fileDescriptionToFind)
{
exeName = GetSpecificFileProperties(filePath, 0).Replace(Environment.NewLine, string.Empty);
break;
}
}
return exeName;
}
Either method (1 or 2) you use I recommend that you save the location of exe name so you only do this operation once. In my opinion its better to use Method 1 as its faster and doesn't create all the "Windows Installer reconfigured the product." event logs.
Alternate Method using an Installer
If your application is being installed you could find out where CMG STARS is located during installation Using Windows Installer to Inventory Products and Patches:
Enumerating Products
Use the MsiEnumProductsEx function to enumerate Windows Installer applications that are installed in the
system. This function can find all the per-machine installations and
per-user installations of applications (managed and unmanaged) for the
current user and other users in the system. Use the dwContext
parameter to specify the installation context to be found. You can
specify any one or any combination of the possible installation
contexts. Use the szUserSid parameter to specify the user context of
applications to be found.
During installation you would find the exe path to CMG STARS and save a registry key with the value.
I discuss using this approach of saving an EXE's install path in the registry for updating applications here.
Tip
As mentioned in the comments, it is worthwhile you do a search in the registry for the EXE's name st201110.exe and see if the authors of the CMG STAR application already provide this information in a registry key you can access directly.
Plan B
If all else fails present the user with a FileOpenDialog and get them to specify the exe's path manually.
What if the 3rd party application is uninstalled or upgraded?
I mentioned to store the install path and exe name in the registry (or database, config file, etc) and you should always check the exe file exists before making any external calls to it, eg:
if (!File.Exists(installPath + exeName))
{
//Run through the process to establish where the 3rd party application is installed
}

Finding Registry Keys in C#

I am working on a project that will allow me to delete the registry key from a Windows 7 PC. Specifically I am trying to make a program that will allow me to delete a profile from the machine via the ProfileList key. My problem is no matter what I try I can't seem to read the key correctly which I want to do before I start randomly deleting stuff. My code is
RegistryKey OurKey = Registry.LocalMachine;
OurKey = OurKey.OpenSubKey(#"SOFTWARE\Microsoft\WindowsNT\CurrentVersion\ProfileList", true);
foreach (string Keyname in OurKey.GetSubKeyNames())
{
MessageBox.Show(Keyname);
}
This code runs but doesn't return anything (No MessageBox). Any ideas why not?
EDIT:
I got the top level keys to load thanks to you all but it does only show the folder/key names (Ex: S-1-5-21-3794573037-2687555854-1483818651-11661) what I need is to read the keys under that folder to see what the ProfilePath is. Would there be a better way to go about that?

As pointed out by Lloyd, your path should use "Windows NT". In case of doubt, always use regedit to go inspect the registry manually.
Edit: To go with your edit, you can simply GetValue on the keys you find, the following code should do what you're looking for:
RegistryKey OurKey = Registry.LocalMachine;
OurKey = OurKey.OpenSubKey(#"SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList", true);
foreach (string Keyname in OurKey.GetSubKeyNames())
{
RegistryKey key = OurKey.OpenSubKey(Keyname);
MessageBox.Show(key.GetValue("KEY_NAME").ToString()); // Replace KEY_NAME with what you're looking for
}

Windows NT
Please do not miss space

Writing to registry in a C# application

I'm trying to write to the registry using my C# app.
I'm using the answer given here: Writing values to the registry with C#
However for some reason the key isn't added to the registry.
I'm using the following code:
string Timestamp = DateTime.Now.ToString("dd-MM-yyyy");
string key = "HKEY_LOCAL_MACHINE\\SOFTWARE\\"+Application.ProductName+"\\"+Application.ProductVersion;
string valueName = "Trial Period";
Microsoft.Win32.Registry.SetValue(key, valueName, Timestamp, Microsoft.Win32.RegistryValueKind.String);
The Application.name and Application.version 'folders' don't exists yet.
Do I have to create them first?
Also, I'm testing it on a 64b Win version so I think if I want to check the registry for the key added I have to specifically check the 32bit registry in: C:\Windows\SysWOW64\regedit.exe don't I?

First of all if you want to edit key under LocalMachine you must run your application under admin rights (better use CurrentUser it's safer or create the key in installer). You have to open key in edit mode too (OpenSubKey method) to add new subkeys. I've checked the code and it works. Here is the code.
RegistryKey key = Registry.LocalMachine.OpenSubKey("Software",true);
key.CreateSubKey("AppName");
key = key.OpenSubKey("AppName", true);
key.CreateSubKey("AppVersion");
key = key.OpenSubKey("AppVersion", true);
key.SetValue("yourkey", "yourvalue");

You can use the following code to create and open the required registry keys.
RegistryKey SoftwareKey = Registry.LocalMachine.OpenSubKey("Software",true);
RegistryKey AppNameKey = SoftwareKey.CreateSubKey("AppName");
RegistryKey AppVersionKey = AppNameKey.CreateSubKey("AppVersion");
AppVersionKey.SetValue("yourkey", "yourvalue");
You can basically use CreateSubKey for all your application settings, as it will open the key for write access, if it already exists, and create it otherwise. There is no need to create first, and then open. OpenSubKey comes in handy when you are absolutely certain the key already exists, like in this case, with "HKEY_LOCAL_MACHINE\SOFTWARE\"

Also check if your registry calls are getting virtualised. See here for more information.
It can happen if your application is not UAC aware and occurs for compatibility reasons.
Real path
HKEY_LOCAL_MACHINE\Software\FooKey
Virtual path
HKEY_USERS\<User SID>_Classes\VirtualStore\Machine\Software\FooKey

Try to open HKLM\Software first. Then create key for your program, and then create key for version. Howewer, your key could be placed at HKLM\software\WOW6432Node. Check this.

The problem is you don't have enough privileges. Here is a way that works for my:
RegistryKey myKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64);
myKey = myKey.OpenSubKey(subkey, RegistryKeyPermissionCheck.ReadWriteSubTree, RegistryRights.FullControl);
if (myKey != null)
{
myKey.SetValue("DefaultPrinterId", ldiPrinters[e.RowIndex].id, RegistryValueKind.String);
myKey.Close();
}
With RegistryKey.OpenBaseKey you open the correct registry, because when you don't have permissions the registry that you write, it does in another location.

By default, your changes will be written to HKLM\SOFTWARE\WOW6432Node\... because of registry redirection. This can be quite confusing.
In order to write to HKLM\SOFTWARE\..., you need to use RegistryKey.OpenBaseKey to open the 64-bit registry:
var path = #"SOFTWARE\...";
var baseKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64);
var key = baseKey.CreateSubKey(path, RegistryKeyPermissionCheck.ReadWriteSubTree);
key.SetValue(name, value, RegistryValueKind.String);
Also, you need to have permission to write to the specified registry key.
You can get permission either by assigning permissions to specific users or service accounts or by running your app in elevated mode.