Before you try to answer this with, "Do a quick Google search." I'd like to point out that I have already. Here is the situation, I have the following method that attempts to modify a registry key value. The problem I'm getting is that when executed, it throws an UnauthorizedAccessException even though I've opened the key as writeable. I'm running Visual Studio as administrator and even tried to make a small .exe with a manifest file forcing it to run as admin that will execute the code with no luck. The key already exists, it doesn't try to go into the CreateKey method. Here is the block of code.
Path = "S-1-5-21-1644491937-1078145449-682003330-5490\Software\Microsoft\Windows\CurrentVersion\Policies\System"
Key = "DisableTaskMgr"
NewValue = 1
public OperationResult ModifyKey()
{
OperationResult result = new OperationResult();
if (!Path.IsNullOrEmptyTrim())
{
if (!Key.IsNullOrEmptyTrim())
{
try
{
var key = Microsoft.Win32.Registry.Users.OpenSubKey(Path, true);
if (key != null)
{
key.SetValue(Key, NewValue);
key.Close();
}
else
{
result = CreateKey();
}
}
catch (Exception ex)
{
result.SetFail("Error accessing registry", ex);
}
}
else
{
result.SetFail("Registry key was null");
}
}
else
{
result.SetFail("Registry path was null");
}
return result;
}
Do I have to manually walk down the registry tree setting each OpenSubKey call to writeable? I tried this as well, still threw the same error...
in the var for your key
var key = Microsoft.Win32.Registry.Users.OpenSubKey(Path, true);
change to
var key = Microsoft.Win32.Registry.Users.OpenSubKey(Path, RegistryKeyPermissionCheck.ReadWriteSubTree);
Have you tried setting the accessrule and permissions?
string user = Environment.UserDomainName + "\\" + Environment.UserName;
RegistryAccessRule rule = new RegistryAccessRule(user,
RegistryRights.FullControl,
AccessControlType.Allow);
RegistrySecurity security = new RegistrySecurity();
security.AddAccessRule(rule);
var key = Microsoft.Win32.Registry.Users.OpenSubKey(subKeyPath, RegistryKeyPermissionCheck.ReadWriteSubTree, RegistryRights.FullControl);
key.SetAccessControl(security);
One possible issue that I see with your code is that the Path variable is being set to a string that doesn't escape the \ characters. How about something like:
Path = #"S-1-5-21-1644491937-1078145449-682003330-5490\Software\Microsoft\Windows\CurrentVersion\Policies\System";
As a last ditch effort to figure out what was going on, I created a simple service to test this code that will run as the local system account. It's the highest privileges I could think of to try and run the code with. Running the code with these permissions worked.
Special thanks go out to 0_____0 and Charleh for pointing out the anti-virus as well. I checked the logs and it turns out it was trying to quarantine my changes. I guess even it won't stop the System user from making these changes though.
Special thanks go out to Sorceri as well for helping me research this so much.
In conclusion, if you're having intermittent, extremely odd behavior, check your virus scanner and permissions.
I ran into the same problem recently. So I tried a few things and instead of calling key.SetValue(Key, NewValue) simply calling create function solved my problem. That is;
Microsoft.Win32.RegistryKey key1 = Microsoft.Win32.Registry.Users.CreateSubKey(Path);
key1.SetValue(Key, NewValue);
CreateSubKey call doesn't delete the current entry but provided with the ability to write without exception. I hope that helps.
Only set grants to dword. You must to open Registry and at the last folder path, rigth click over it and set Grants, and select All Aplications and check Total Control. I hope to help you.
just Registry.SetValue(sub_key, key, value);
Example:
Registry.SetValue(
#"HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run",
"MyApp",
Application.ExecutablePath);
Related
System.IO.File.Exists(string path)
returns always false, even when the file exists on the specified path. What could be the possible solution?
It could well be a permission problem. From the documentation:
The Exists method returns false if any error occurs while trying to determine if the specified file exists. This can occur in situations that raise exceptions such as passing a file name with invalid characters or too many characters, a failing or missing disk, or if the caller does not have permission to read the file.
One way of seeing what's happening is to just try to read the file (e.g. with File.OpenRead). I'd be surprised if that succeeds - but if it fails, the exception should give you more information.
Hiding file endings in windows can sometimes cause confusion: you KNOW your file is named file.txt when it is actually named file.txt.txt because the last 4 characters have been hidden by the OS.
One possibility not mentioned in any of the answers here is 'File System Redirection' on Windows 8.1 onward.
For example, if your program is a 32-bit application and you're running on 64-bit Windows then an attempt to access %windir%\System32 would be redirected to %windir%\SysWOW64. And if the file you're trying to access doesn't exist in %windir%\SysWOW64 then System.IO.File.Exists(string path) would return False.
Link to a nice article explaining this behavior
I was puzzling over this as well, then realized I was using File.Exists when I should have been using Directory.Exists.
in my case, a different "dash" in file name causes the issue.
var f1 = "4-37R.pdf";
var f2 = "4‐37R.pdf";
var r = f1==f2?"same":"diff";
Console.Write(r); //diff
turns out
var c1 = '-';
var c2 = '‐';
Console.WriteLine((int)c1); //45
Console.WriteLine((int)c2); //8208
use the same '-' fixes the issue.
How I got around this was using Server.MapPath(fileName) as it kept trying to find the file somewhere else.
System.IO.File.Exists(Server.MapPath(string path))
This had me stumped for a while while I was debugging a service locally, I was running File.Exists("U:\dir1") against a server location mapped on my workstation as (U:). I replaced the U:\dir1 to "\\serverPath\dir1" and File.Exists then returned true.
I was experiencing this myself too. In my case, I was deleting the file and re-creating it. In the process that was deleting the file, I forgot to add in WaitForExit() before using File.Exists later on
I just learned today that System.IO.File.Exists will return false if the file exists but is empty
System.IO.File.Exists(string path) returned false for me while trying to read C:\OpenSSL\bin\file.txt.
Running the application in Administrator mode did not help.
(I was logged on the administrator account, Windows 10)
Once I moved the file to C:\Users\MyUser\Desktop\file.txt, File.Exists() returned true.
Here's one more, which took me far too long to twig to.
The file name was in a constructed variable that was use to write the file, then the same variable used to check that it had been successfully written, so it could not have been different versions of '-'. I am running mono on Linux and debugging as a different user than the program is normally run by/as. Many of these types of errors are related to permissions and I spent a while banging my head on that. When File.OpenRead also threw "file not found" I finally noticed my file name had a space character at the end. I only saw this when I copied the exception message, which showed quote marks around the file name string, revealing the included space.
Apparently you can write a file name with a trailing space, but File.Exists trims that off and doesn't recognize it. When I eliminated the trailing space File.Exists worked as expected.
There can be requirement to use the DirectoryProvider Refresh() process to get the correct result from the Exists function.
e.g. code as per:
private DirectoryInfo CreateDirectory(string folderPath, int code, string message)
{
DirectoryInfo di;
try
{
di = DirectoryProvider.CreateDirectory(folderPath);
}
catch
{
throw new WebServiceException(code, HttpStatusCode.BadRequest, message);
}
di.Refresh();
if (!DirectoryProvider.Exists(di))
{
throw new WebServiceException(code, HttpStatusCode.BadRequest, message);
}
return di;
}
I was using System.IO.Path.Combine and assuming it would remove any trailing white space. For the life of me I could figure out why System.IO.File.Exists(path) was returning false.
I used the below snippet to test why it was failing
Turns out that a trailing white space was introduced causing an
"The filename, directory name, or volume label syntax is incorrect inside batch"
Hopefully someone will avoid the same stupid mistake as me
bool FileExists(string path){
try
{
using var stream = File.Open(path, FileMode.Open);
return true;
}
catch (FileNotFoundException)
{
return false;
}
catch (DirectoryNotFoundException)
{
return false;
}
catch (UnauthorizedAccessException ex)
{
Console.WriteLine(ex.message);
throw;
}
catch (Exception ex)
{
Console.WriteLine(ex.message);
throw;
}
}
I want to retrieve the value from registry. For example like: HKEY_LOCAL_MACHINE\SOFTWARE\Manufacturer's name\Application name\InstallInfo
Under the 'InstallInfo' there are so many variables, like
ProductVersion, WebsiteDescription, WebSiteDirectory, CustomerName, WebSitePort etc.
I want to retrieve some values of these variables. I tried the following code but it returns
'Object reference not set to an instance of an object'
var regKey = Registry.LocalMachine;
regKey = regKey.OpenSubKey(#"SOFTWARE\ABC Limited\ABC Application\InstallInfo");
if (regKey == null)
{
Console.WriteLine("Registry value not found !");
}
else
{
string dirInfo = (string)regKey.GetValue("WebSiteDirectory");
Console.Write("WebSiteDirectory: " + dirInfo);
}
Console.ReadKey();
OpenSubKey returns null when it fails. That's clearly what's happening here.
It's failing because you are looking under the wrong root key. You are looking under HKCU but the key is under HKLM.
So you need
RegistryKey regKey = Registry.LocalMachine.OpenSubKey(
#"SOFTWARE\Manufacturer's name\Application name\InstallInfo");
You must always check the return value when you call OpenSubKey. If it is null then handle that error case.
if (regKey == null)
// handle error, raise exception etc.
The other thing to watch out for is the registry redirector. If your process is a 32 bit process running on a 64 bit system, then you will see the 32 bit view of the registry. That means that your attempt to view HKLM\Softare is transparently redirected to HKLM\Software\Wow6432Node.
Before you convert regKey.GetValue("WebSiteDirectory") to string, You should check it if it is null or not,
if (regKey.GetValue("WebSiteDirectory")!=null)
//do the rest
It may be because you are looking under wrong root key.
It should be:
Registry.CurrentUser
instead of
Registry.LocalMachine
Here you go:
Registry.LocalMachine.CreateSubKey(#"SOFTWARE\Manufacturer's name\Application name\InstallInfo");
I have a issue reading a registry value programmatically using C#.
I looked into many sites and help but could not find any helpful.
I am able to access and read registry when I run VS in eleveated mode, but face issue when I run VS with out elevated mode.
Initially I started with the below code
byte[] val = (byte[])Registry.GetValue("HKEY_LOCAL_MACHINE\\Software\\MyServices\\Identity\\ASPNET_SETREG", "ValueName", 0);
This worked fine with elevated mode, but fails in non elevated mode.
Placed the attribute on top of the function
[RegistryPermissionAttribute(SecurityAction.Demand,Unrestricted=true)]
This did not help. Then Tried
[System.Security.Permissions.SecurityPermission(System.Security.Permissions.SecurityAction.LinkDemand, Flags = System.Security.Permissions.SecurityPermissionFlag.AllFlags)]
Still did not work.
Now I Tried the below code...
RegistryKey key = Registry.LocalMachine;
RegistrySecurity rs = new RegistrySecurity();
rs = key.GetAccessControl();
string user = "DomainName\\Username";
rs.AddAccessRule(new RegistryAccessRule(user,
RegistryRights.ReadKey,
InheritanceFlags.None,
PropagationFlags.None,
AccessControlType.Allow));
key.SetAccessControl(rs);//Exception: "Attempted to perform an unauthorized operation."}
//RegistryKey key2 = key.OpenSubKey("Software\\MyServices\\Identity\\ASPNET_SETREG");
//RegistryKey key2 = key.OpenSubKey("Software\\MyServices\\Identity\\ASPNET_SETREG", false);
//RegistryKey key2 = key.OpenSubKey("Software\\MyServices\\Identity\\ASPNET_SETREG", RegistryKeyPermissionCheck.ReadSubTree);
RegistryKey key2 = key.OpenSubKey("Software\\MyServices\\Identity\\ASPNET_SETREG", RegistryKeyPermissionCheck.ReadSubTree, RegistryRights.ReadPermissions);
Commenting SetAccessControl and use any of the OpenSubkey option, I get Exception: "Requested registry access is not allowed."
I am badly stuckup and unable to proceed.
private RegistryKey keyR = Registry.CurrentUser.OpenSubKey("Software\\YourKey",true);
private RegistryKey keyW = Registry.CurrentUser.CreateSubKey("Software\\YourKey");
public string version
{
get { return keyR.GetValue("VERSION", "", RegistryValueOptions.DoNotExpandEnvironmentNames).ToString(); }
set { keyW.SetValue("VERSION", value, RegistryValueKind.String); }
}
I am using windows registry in this way. No problem...
The windows registry is basically a structured file system, and has permissions for keys and values.
You do not have the permissions set correctly on ...\MyServices\ or deeper keys - you have no permission to access those from your unprivileged process.
Either:
Those keys should be readable by anybody, so you should change the permissions to make them readable by everybody. Or -
Those keys were intentionally restricted for a good reason, and so they should not be readable by everybody, in which case your program should always run elevated.
I have created the following registry key (copied through regedit):
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\test
I would like to now delete this registry key, and so... I have been using the following code and am running into a small error.
RegistryKey regKey;
string regPath_Key = #"Software\Microsoft\Windows\CurrentVersion\test";
regKey = Registry.CurrentUser.OpenSubKey(regPath_Key, true);
if(regKey != null) // Always returns null, even though the key does exist.
{
Registry.CurrentUser.DeleteSubKey(regPath_Key, true);
}
The issue I am having is that the line if(regKey != null) always returns null! I have gone back and checked that the key does in fact exist multiple times - but still the same result. I am going to assume my code has issues somewhere?
Could it be that you are on a 64 bit machine and your project is set to x86 architecture? in that case, verify that the key you state exists under HKCU\Software\Wow6432Node... as every path is redirected to this 32 bit process registry...
You should not include HKEY_CURRENT_USER in the string you pass to Registry.CurrentUser.OpenSubKey(). Instead use
string regPath_Key = #"Software\Microsoft\Windows\CurrentVersion\test";
The following code is not working for me:
public bool createRegistry()
{
if (!registryExists())
{
Microsoft.Win32.Registry.LocalMachine.CreateSubKey("Software\\xelo\\");
Microsoft.Win32.Registry.LocalMachine.OpenSubKey("Software\\xelo").SetValue("hostname", (string)hostname, Microsoft.Win32.RegistryValueKind.String);
return true;
}
else
{
return updateRegistry();
}
}
Exception:
System.UnauthorizedAccessException | "Cannot write to the registry
key"
Non-admin and unelevated admin users don't have rights to modify the HKEY_LOCAL_MACHINE key. Run the program 'as administrator'.
Below code to create key in the registry.
Microsoft.Win32.RegistryKey key;
key = Microsoft.Win32.Registry.LocalMachine.CreateSubKey("Software\\Wow6432Node\\Names");
key.SetValue("Name", "Isabella");
key.Close();
Even when admin I don't think you can create new keys off LocalMachine. Make sure that you do
Registry.LocalMachine.CreateSubKey(#"SOFTWARE\YourCompanyName\SomeNewKey");
and not
Registry.LocalMachine.CreateSubKey("SomeNewKey");
Well you've got your answer already - I'm guessing you're running on Vista or Windows 7 (or Server 2008) and the process/user running the app doesn't have rights/permission to modify the registry.
So its not a code problem as such but a systems admin one. Build the app and run as administrator and see if that works.
Set the Premission Check bit to true...
Microsoft.Win32.Registry.LocalMachine.CreateSubKey("Software\\xelo\\", true);
:)