I've been working on an installer package and using RegistryKey.OpenBaseKey to work with custom actions that either open and add/remove keys to/from the 64-bit registry or the 32-bit registry from an MSI package, but this requires me to install .NET Framework 4 on the target machine before running my installer, using a bootstrapper or something else, because OpenBaseKey was only introduced in .NET Framework 4. Ideally, I would like to target just .NET Framework 3.5 and still be able to modify either the 64-bit or 32-bit registry hives like in OpenBaseKey; then I wouldn't need .NET 4 and the overhead of installing it.
Are there alternatives to OpenBaseKey for those of us who would not like to make .NET 4 a prerequisite? Something like P/Invoking a certain WinAPI method to kick this off, perhaps? I'm not sure what it would take.
For anyone who is interested in a C# solution for some of the previous versions of .NET in order to not have to refactor too much code, its not pretty but here it is, totally doable using reflection. I found this trick in the XSharper source code.
public static class RegistryExtensions
{
public enum RegistryHiveType
{
X86,
X64
}
static Dictionary<RegistryHive, UIntPtr> _hiveKeys = new Dictionary<RegistryHive, UIntPtr> {
{ RegistryHive.ClassesRoot, new UIntPtr(0x80000000u) },
{ RegistryHive.CurrentConfig, new UIntPtr(0x80000005u) },
{ RegistryHive.CurrentUser, new UIntPtr(0x80000001u) },
{ RegistryHive.DynData, new UIntPtr(0x80000006u) },
{ RegistryHive.LocalMachine, new UIntPtr(0x80000002u) },
{ RegistryHive.PerformanceData, new UIntPtr(0x80000004u) },
{ RegistryHive.Users, new UIntPtr(0x80000003u) }
};
static Dictionary<RegistryHiveType, RegistryAccessMask> _accessMasks = new Dictionary<RegistryHiveType, RegistryAccessMask> {
{ RegistryHiveType.X64, RegistryAccessMask.Wow6464 },
{ RegistryHiveType.X86, RegistryAccessMask.WoW6432 }
};
[Flags]
public enum RegistryAccessMask
{
QueryValue = 0x0001,
SetValue = 0x0002,
CreateSubKey = 0x0004,
EnumerateSubKeys = 0x0008,
Notify = 0x0010,
CreateLink = 0x0020,
WoW6432 = 0x0200,
Wow6464 = 0x0100,
Write = 0x20006,
Read = 0x20019,
Execute = 0x20019,
AllAccess = 0xF003F
}
[DllImport("advapi32.dll", CharSet = CharSet.Auto)]
public static extern int RegOpenKeyEx(
UIntPtr hKey,
string subKey,
uint ulOptions,
uint samDesired,
out IntPtr hkResult);
public static RegistryKey OpenBaseKey(RegistryHive registryHive, RegistryHiveType registryType)
{
UIntPtr hiveKey = _hiveKeys[registryHive];
if (Environment.OSVersion.Platform == PlatformID.Win32NT && Environment.OSVersion.Version.Major > 5)
{
RegistryAccessMask flags = RegistryAccessMask.QueryValue | RegistryAccessMask.EnumerateSubKeys | RegistryAccessMask.SetValue | RegistryAccessMask.CreateSubKey | _accessMasks[registryType];
IntPtr keyHandlePointer = IntPtr.Zero;
int result = RegOpenKeyEx(hiveKey, String.Empty, 0, (uint)flags, out keyHandlePointer);
if (result == 0)
{
var safeRegistryHandleType = typeof(SafeHandleZeroOrMinusOneIsInvalid).Assembly.GetType("Microsoft.Win32.SafeHandles.SafeRegistryHandle");
var safeRegistryHandleConstructor = safeRegistryHandleType.GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic, null, new[] { typeof(IntPtr), typeof(bool) }, null); // .NET < 4
if (safeRegistryHandleConstructor == null)
safeRegistryHandleConstructor = safeRegistryHandleType.GetConstructor(BindingFlags.Instance | BindingFlags.Public, null, new[] { typeof(IntPtr), typeof(bool) }, null); // .NET >= 4
var keyHandle = safeRegistryHandleConstructor.Invoke(new object[] { keyHandlePointer, true });
var net3Constructor = typeof(RegistryKey).GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic, null, new[] { safeRegistryHandleType, typeof(bool) }, null);
var net4Constructor = typeof(RegistryKey).GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic, null, new[] { typeof(IntPtr), typeof(bool), typeof(bool), typeof(bool), typeof(bool) }, null);
object key;
if (net4Constructor != null)
key = net4Constructor.Invoke(new object[] { keyHandlePointer, true, false, false, hiveKey == _hiveKeys[RegistryHive.PerformanceData] });
else if (net3Constructor != null)
key = net3Constructor.Invoke(new object[] { keyHandle, true });
else
{
var keyFromHandleMethod = typeof(RegistryKey).GetMethod("FromHandle", BindingFlags.Static | BindingFlags.Public, null, new[] { safeRegistryHandleType }, null);
key = keyFromHandleMethod.Invoke(null, new object[] { keyHandle });
}
var field = typeof(RegistryKey).GetField("keyName", BindingFlags.Instance | BindingFlags.NonPublic);
if (field != null)
field.SetValue(key, String.Empty);
return (RegistryKey)key;
}
else if (result == 2) // The key does not exist.
return null;
throw new Win32Exception(result);
}
throw new PlatformNotSupportedException("The platform or operating system must be Windows XP or later.");
}
}
Example usage:
var key64 = RegistryExtensions.OpenBaseKey(RegistryHive.LocalMachine, RegistryExtensions.RegistryHiveType.X64);
var key32 = RegistryExtensions.OpenBaseKey(RegistryHive.LocalMachine, RegistryExtensions.RegistryHiveType.X86);