Access 64-bit HKLM\Software registry by 32-bit C#.NET application
While running 32-bit windows application on a 64-bit windows OS their is a registry redirection. Here if 32-bit application try to read a key under HKLM\Software, then due to Registry redirection effective path becomes HKLM\Software\Wow6432Node. For example, we are running 64-bit and 32-bit application to read registry keys as HKLM\Software\xyz and HKLM\Software\Wow6432Node\xyz
So by default with an input of HKLM\Software, 64-bit application will read HKLM\Software\xyz while because of registry redirection 32-bit application will read HKLM\Software\Wow6432Node\xyz.
In C#, to read 64-bit HKLM\Software registry keys we can use RegistryKey.OpenBaseKey method. This method takes two arguments- RegistryHive and RegistryView. Here sperate registry views are present for 32-bit and 64-bit.
Here is the sample C# code to read AppPaths for 32-bit and 64-bit applications installed on the system -
While running 32-bit windows application on a 64-bit windows OS their is a registry redirection. Here if 32-bit application try to read a key under HKLM\Software, then due to Registry redirection effective path becomes HKLM\Software\Wow6432Node. For example, we are running 64-bit and 32-bit application to read registry keys as HKLM\Software\xyz and HKLM\Software\Wow6432Node\xyz
So by default with an input of HKLM\Software, 64-bit application will read HKLM\Software\xyz while because of registry redirection 32-bit application will read HKLM\Software\Wow6432Node\xyz.
In C#, to read 64-bit HKLM\Software registry keys we can use RegistryKey.OpenBaseKey method. This method takes two arguments- RegistryHive and RegistryView. Here sperate registry views are present for 32-bit and 64-bit.
Here is the sample C# code to read AppPaths for 32-bit and 64-bit applications installed on the system -
try
{
string AppPath = @"SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths";
RegistryKey rkbase = null;
rkbase = RegistryKey.OpenBaseKey(Microsoft.Win32.RegistryHive.LocalMachine, RegistryView.Registry32);
using (RegistryKey rk = rkbase.OpenSubKey(uninstallKey))
{
foreach (string skName in rk.GetSubKeyNames())
{
using (RegistryKey sk = rk.OpenSubKey(skName))
{
try
{
if (sk.GetValue("Path") != null)
{
//add this to required list
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
}
if (Environment.Is64BitOperatingSystem)
{
using (RegistryKey rk = Registry.LocalMachine.OpenSubKey(AppPath))
{
foreach (string skName in rk.GetSubKeyNames())
{
using (RegistryKey sk = rk.OpenSubKey(skName))
{
try
{
if (sk.GetValue("Path") != null)
{
//add this to required list
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
Here Environment.Is64BitOperatingSystem is used to check if the current system is 64-bit or not. This function is avialable with .net framework 4.0
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