Read a Registry Key

Read a Registry Key

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I have a web application which is importing DLLs from the bin folder.

const string dllpath = "Utility.dll";

    [DllImport(dllpath)]

Now what I want to do is first import the DLLs from a folder not in the current project but at some different location.

The path of that folder is stored in a registry key.

How should I do this?

Edit:

Why can't I work this out???

public partial class Reports1 : System.Web.UI.Page
{

    RegistryKey registryKey = Registry.CurrentUser.OpenSubKey(@"Software\xyz");
    string pathName = (string)registryKey.GetValue("BinDir");

    const string dllpath = pathName;
    [DllImport(dllpath)]
    public static extern bool GetErrorString(uint lookupCode, [MarshalAs(UnmanagedType.LPWStr)] StringBuilder buf, uint bufSize);

    protected void Page_Load(object sender, EventArgs e)
    {

string pathName = (string)registryKey.GetValue("BinDir"); is not working here, but is working in the pageload event...

But if I do this DLL import won't work... How can I fix this?


Reading the registry is pretty straightforward. The Microsoft.Win32 namespace has a Registry static class. To read a key from the HKLM node, the code is:

RegistryKey registryKey = Registry.LocalMachine.OpenSubKey("Software\\NodeName")

If the node is HKCU, you can replace LocalMachine with CurrentUser.

Once you have the RegistryKey object, use GetValue to get the value from the registry. Continuing Using the example above, getting the pathName registry value would be:

string pathName = (string) registryKey.GetValue("pathName");

And don't forget to close the RegistryKey object when you are done with it (or put the statement to get the value into a Using block).

Updates

I see a couple of things. First, I would change pathName to be a static property defined as:

Private static string PathName
{ 
    get
    {
         using (RegistryKey registryKey = Registry.CurrentUser.OpenSubKey(@"Software\Copium"))
         {
              return (string)registryKey.GetValue("BinDir");
         }
    }
}

The two issues were:

  1. The RegistryKey reference will keep the registry open. Using that as a static variable in the class will cause issues on the computer.
  2. Registry path's use forward slashes, not back slashes.

How to: Read a Value from a Registry Key, You need to first add using Microsoft.Win32; to your code page. Then you can begin to use the Registry classes: try { using (RegistryKey key  To read a value from a registry key. Use the GetValue method, specifying the path and name) to read a value from registry key. The following example reads the value Name from HKEY_CURRENT_USER\Software\MyApp and displays it in a message box. Dim readValue = My.Computer.Registry.GetValue( "HKEY_CURRENT_USER\Software\MyApp", "Name", Nothing) MsgBox("The value is " & readValue) This code example is also available as an IntelliSense code snippet.


None of these answers worked for me. This is what I used:

static void Main()
{
    const string dotNetFourPath = "Software\\Microsoft";//note backslash
    using (RegistryKey registryKey = Registry.LocalMachine.OpenSubKey(dotNetFourPath))
    {
        Console.WriteLine(registryKey.SubKeyCount);//registry is not null
        foreach (var VARIABLE in registryKey.GetSubKeyNames())
        {
            Console.WriteLine(VARIABLE);//here I can see I have many keys
            //no need to switch to x64 as suggested on other posts
        }
    }
}

How to read value of a registry key c#, A registry key that has a parent key is called a subkey. You can use Get-ChildItem to view registry keys and Set-Location to navigate to a key path. Registry values are attributes of a registry key. In the Registry drive, they are called Item Properties. A registry key can contain one value that is not associated with any name. When this unnamed value is displayed in the registry editor, the string "(Default)" appears instead of a name. To retrieve this unnamed value, specify either null or the empty string ("") for valueName .


All these answers may lead to problems running on 64bit OS - which is usual nowadays.

In my situation, i compile to 'Any CPU' target and the software is working fine when i install on 64bit OS. But my unit tests are running into problems - obviously they are executed in 32bit mode.

In this case not the HKEY_LOCAL_MACHINE\SOFTWARE\MyCompany\MySoftware is searched but HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\MyCompany\MySoftware but there are no entries!

In this situation we have to specify the start point of our search using

RegistryKey hklm = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64)

In total we can use.

string configurationDirectory = string.Empty;

using (RegistryKey hklm = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64))
{
    using (RegistryKey registryKey = hklm.OpenSubKey(@"SOFTWARE\MyCompany\MySoftware"))
    {
        if (registryKey != null)
        {
            configurationDirectory = (string)registryKey.GetValue("ConfigurationDirectory");
        }
    }
}

How do I read values of registry keys?, The output will display all the keys and values under the registry key. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Windows\. This location in the  C# Read And Write A Registry Key This example shows how to read and write a registry key. To do this, we must use RegistryKey and Registry classes in Microsoft.Win32 namespace.


try
{
    RegistryKey regKey = Registry.LocalMachine;
    regKey = regKey.OpenSubKey(@"Software\Application\");

    if (regKey != null)
    {
        return regKey.GetValue("KEY NAME").ToString();
    }
    else
    {
        return null;
    }
}
catch (Exception ex)
{
  return null;
}

Batch Script - Reading from the Registry, Description. The Get-ItemProperty cmdlet gets the properties of the specified items. For example, you can use this cmdlet to get the value of the LastAccessTime property of a file object. You can also use this cmdlet to view registry entries and their values. Reading the registry is pretty straightforward. The Microsoft.Win32 namespace has a Registry static class. To read a key from the HKLM node, the code is: RegistryKey registryKey = Registry.LocalMachine.OpenSubKey("Software\\NodeName") If the node is HKCU, you can replace LocalMachine with CurrentUser.


You can use this:

/// <summary>
/// To read a registry key.
/// input: KeyName (string)
/// output: value (string) 
/// </summary>
public string Read(string KeyName)
{
    // Opening the registry key
    RegistryKey rk = baseRegistryKey ;
    // Open a subKey as read-only
    RegistryKey sk1 = rk.OpenSubKey(subKey);
    // If the RegistrySubKey doesn't exist -> (null)
    if ( sk1 == null )
    {
        return null;
    }
    else
    {
        try 
        {
            // If the RegistryKey exists I get its value
            // or null is returned.
            return (string)sk1.GetValue(KeyName.ToUpper());
        }
        catch (Exception e)
        {
            // AAAAAAAAAAARGH, an error!
            ShowErrorMessage(e, "Reading registry " + KeyName.ToUpper());
            return null;
        }
    }
}

For more information visit this web site .

Get-ItemProperty, It provides RegistryKey objects of the root keys and several static methods to access key/value pairs. RegistryKey class. An instance of this class  Hi all, welcome back, Today I’ll share with you a couple of VBScript samples I developed the other day. They use WMI and its StdRegProv class to read the Windows registry. This sample will take a registry key and show its subkeys and the values within those subkeys:‘ Constants (taken from WinReg.h) ‘ Const HKEY_CLASSES_ROOT


Read and Write Windows Registry to Store Data Using C#, This example shows how to read and write a registry key. To do this, we must use RegistryKey and Registry classes in Microsoft. Listing All Subkeys of a Registry Key. You can show all items directly within a registry key by using Get-ChildItem. Add the optional Force parameter to display hidden or system items. For example, this command displays the items directly within PowerShell drive HKCU:, which corresponds to the HKEY_CURRENT_USER registry hive:


C# Read And Write A Registry Key, In this key, you see the SOFTWARE folder, then Microsoft, Windows, CurrentVersion, and finally the Run folder. HKEY_LOCAL_MACHINE\  Reading from the registry is done via the REG QUERY command. This command can be used to retrieve values of any key from within the registry. Syntax REG QUERY [ROOT\]RegKey /v ValueName [/s] REG QUERY [ROOT\]RegKey /ve --This returns the (default) value Where RegKey is the key which needs to be searched for in the registry. Example


How do I open and edit the Windows Registry Editor?, The following method can be used to read a value from a sub key. static string ReadSubKeyValue(string subKey, string key). {. string str = string. Omitting \\ComputerName\ causes the operation to default to the local computer. The KeyName must include a valid root key. Valid root keys for the local computer are: HKLM, HKCU, HKCR, HKU, and HKCC. If a remote computer is specified, valid root keys are: HKLM and HKU. /v <ValueName> Specifies the registry value name that is to be queried.