I am using the cookie cutter code to get a registry key object in C#:
RegistryKey reg = Registry.LocalMachine.OpenSubKey("SOFTWARE\\MyNewKeyName\\");
After I run this code reg = null. However, if I switch the value passed to OpenSubKey to be any value in the registry under SOFTWARE that has additional nodes below it reg will now have a value. I've tried multiple keys with this pattern and it works. If I put any any key name that does not have additional child nodes it does not work. Ultimately I'm trying to read a string value inside of MyNewKeyName.
Why does my code not work and reg get populated if my key does not have any additional nodes below it?
Well it turns out that the values in the '32-bit' registry and the '64-bit' registry are not identical. So when viewing the registry via 'regedit' and seeing everything, programatically you may not and that's the issue I was running into. I noticed this by running GetSubKeyNames() and inspecting the keys returned. The quick answer is to check both versions of the registry to find the value sought:
//Check the 64-bit registry for "HKEY_LOCAL_MACHINE\SOFTWARE" 1st:
RegistryKey localMachineRegistry64 = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64);
RegistryKey reg64 = localMachineRegistry64.OpenSubKey(registryKeyLocation, false);
if (reg64 != null)
{
return reg64.GetValue(registryKeyName, true).ToString();
}
//Check the 32-bit registry for "HKEY_LOCAL_MACHINE\SOFTWARE" if not found in the 64-bit registry:
RegistryKey localMachineRegistry32 = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32);
RegistryKey reg32 = localMachineRegistry32.OpenSubKey(registryKeyLocation, false);
if (reg32 != null)
{
return reg32.GetValue(registryKeyName, true).ToString();
}
I think the problem is you are compiling it as x86 instead of compiling it as an x64 application. Follow the below steps:
Right click on Project
Select Properties
Select the Build tab
Change "Platform Target" to "x64"
Now run the project.
Related
Here is my c# code:
using (RegistryKey key = Registry.LocalMachine.OpenSubKey(#"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile", true))
{
key.CreateSubKey("NetworkThrottlingIndex");
key.SetValue("NetworkThrottlingIndex", "0000000a", RegistryValueKind.DWord);
key.CreateSubKey("SystemResponsiveness");
key.SetValue("SystemResponsiveness", "00000000", RegistryValueKind.DWord);
key.CreateSubKey("NoLazyMode");
key.SetValue("NoLazyMode", "1");
}
So what is happening here is that I am getting an error
System.NullReferenceException
on the line
key.CreateSubKey("NetworkThrottlingIndex");
because the key is null.
I checked several times but this key is present in my registry editor.
Any idea about what is wrong here?
The SOFTWARE registry key is redirected depending on the bitness of your application and Windows.
To access your key via a x86/32bit EXE (on 64 bit Windows) request the 64 bit Registry View:
using (var hklm = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64))
using (var key = hklm.OpenSubKey(#"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile", RegistryKeyPermissionCheck.ReadWriteSubTree))
{
...
}
Also note that NetworkThrottlingIndex is a sub-key (i.e. a "Folder") and thus you cannot set its value as it has none. Additionally you would use hex literals for the DWORD values (0x0000000a) rather that strings.
I want to delete a folder named EXAMPLE and all values in it in registry that is found under "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\EXAMPLE"
i have tried this ( with true at the end aswell )
Microsoft.Win32.Registry.LocalMachine.DeleteSubKeyTree(#"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\EXAMPLE");
and tried this
string keyName = #"HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall";
using (RegistryKey key = Registry.LocalMachine.OpenSubKey(keyName, true))
{
key.DeleteSubKeyTree("EXAMPLE", true);
}
They either throw me a null exception or argument exception.
How can i just delete an entire folder with all its keys ?
So that i can have the similar effect from batch :
REG DELETE "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\EXAMPLE" /f
The path is incorrect, Registry.LocalMachine doesn't have such a sub key #"HKEY_LOCAL_MACHINE\...". You need to start from "SOFTWARE\..".
string keyName = #"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall";
And from your feedback, your program is affected by the Registry Redirector, in which HKEY_LOCAL_MACHINE\Software is redirected to HKEY_LOCAL_MACHINE\Software\Wow6432Node for a 32-bit program, recompile your program from AnyCPU (Prefer 32-bit) to x64 gets rid of the redirection.
The mechanism of Registry Redirector varies on different Windows versions, so I leave this to you for further reading to understand why 64/32 matters in this case.
I am attempting to create a key in the HKCU\SOFTWARE\Classes\CLSID using the following code:
var softwareKey = Registry.CurrentUser;
var key = softwareKey?.OpenSubKey("SOFTWARE\\Classes\\CLSID", true);
key = key?.CreateSubKey("{220176f5-8cff-4e42-b20c-c2d6b32b133c}", RegistryKeyPermissionCheck.ReadWriteSubTree);
key?.SetValue("", "test value");
It doesn't add the entry, it doesn't raise an error and nothing whatsoever appears in ProcessMonitor.
This is true running visual studio as Administrator, but also running as a regular user.
Any ideas?
Courtesy of AlexK, the answer to this was that the entry was being written due to 64 bit registry redirection - the entries were being written to HKEY_CURRENT_USER\SOFTWARE\Classes\WOW6432Node\CLSID.
And I have found the solution to target the standard node on a 64-bit windows installation is to use RegistryKey.OpenBaseKey as follows:
var softwareKey = RegistryKey.OpenBaseKey(RegistryHive.CurrentUser, RegistryView.Registry64);
You can refer below example :-
RegKey = Registry.LocalMachine.OpenSubKey("SOFTWARE\Classes\WOW6432Node\CLSID\", True)
RegKey.CreateSubKey("{00000000-EAF8-3196-9360-1AADDCDABE1B}")
RegKey.Close()
Reference link :-
https://www.codeproject.com/Questions/273588/How-to-create-a-guid-key-under-HKEY-CLASSES-ROOT-C
Edit 1:
Another example :-
Microsoft.Win32.RegistryKey key;
key = Microsoft.Win32.Registry.CurrentUser.CreateSubKey("Names");
key.SetValue("Name", "Isabella");
key.Close();
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
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.