Win32 API function to programmatically enable/disable device
You can enable/disable devices from Win32 (and hence from C# via P/Invoke) using the SetupDi APIs but not all devices are "disable-able" in this way.
The problem you'll run into trying to disable your touchpad from Win32 (or WMI or any other API which calls down into the SetupDi* family of functions) is that the default mouse driver which is in most laptops with a touchpad ("PS/2 compatible mouse") doesn't support being disabled using SetupDi API's. I suspect this may be because actual old mice using PS/2 connectors can't be hot-detached without hosing the hardware.
To verify that you can't disable, go into Device Manager and right-click on your mouse driver. If you see a disable option, you can use SetupDi to disable it. If no disable option, you're out of luck... welcome to IOCTL-land!
If you do see a disable option, then the code below (ported to C# from a VB sample I found here) should let you disable and re-enable the device.
Here's the code to call the library:
public static void EnableMouse(bool enable)
{
// every type of device has a hard-coded GUID, this is the one for mice
Guid mouseGuid = new Guid("{4d36e96f-e325-11ce-bfc1-08002be10318}");
// get this from the properties dialog box of this device in Device Manager
string instancePath = @"ACPI\PNP0F03\4&3688D3F&0";
DeviceHelper.SetDeviceEnabled(mouseGuid, instancePath, enable);
}
Here's the library itself, adapted from here.
using System;
using System.Text;
using System.Collections.Generic;
using DisableDevice;
using System.Runtime.InteropServices;
using System.ComponentModel;
using Microsoft.Win32.SafeHandles;
using System.Security;
using System.Runtime.ConstrainedExecution;
using System.Management;
namespace DisableDevice
{
[Flags()]
internal enum SetupDiGetClassDevsFlags
{
Default = 1,
Present = 2,
AllClasses = 4,
Profile = 8,
DeviceInterface = (int)0x10
}
internal enum DiFunction
{
SelectDevice = 1,
InstallDevice = 2,
AssignResources = 3,
Properties = 4,
Remove = 5,
FirstTimeSetup = 6,
FoundDevice = 7,
SelectClassDrivers = 8,
ValidateClassDrivers = 9,
InstallClassDrivers = (int)0xa,
CalcDiskSpace = (int)0xb,
DestroyPrivateData = (int)0xc,
ValidateDriver = (int)0xd,
Detect = (int)0xf,
InstallWizard = (int)0x10,
DestroyWizardData = (int)0x11,
PropertyChange = (int)0x12,
EnableClass = (int)0x13,
DetectVerify = (int)0x14,
InstallDeviceFiles = (int)0x15,
UnRemove = (int)0x16,
SelectBestCompatDrv = (int)0x17,
AllowInstall = (int)0x18,
RegisterDevice = (int)0x19,
NewDeviceWizardPreSelect = (int)0x1a,
NewDeviceWizardSelect = (int)0x1b,
NewDeviceWizardPreAnalyze = (int)0x1c,
NewDeviceWizardPostAnalyze = (int)0x1d,
NewDeviceWizardFinishInstall = (int)0x1e,
Unused1 = (int)0x1f,
InstallInterfaces = (int)0x20,
DetectCancel = (int)0x21,
RegisterCoInstallers = (int)0x22,
AddPropertyPageAdvanced = (int)0x23,
AddPropertyPageBasic = (int)0x24,
Reserved1 = (int)0x25,
Troubleshooter = (int)0x26,
PowerMessageWake = (int)0x27,
AddRemotePropertyPageAdvanced = (int)0x28,
UpdateDriverUI = (int)0x29,
Reserved2 = (int)0x30
}
internal enum StateChangeAction
{
Enable = 1,
Disable = 2,
PropChange = 3,
Start = 4,
Stop = 5
}
[Flags()]
internal enum Scopes
{
Global = 1,
ConfigSpecific = 2,
ConfigGeneral = 4
}
internal enum SetupApiError
{
NoAssociatedClass = unchecked((int)0xe0000200),
ClassMismatch = unchecked((int)0xe0000201),
DuplicateFound = unchecked((int)0xe0000202),
NoDriverSelected = unchecked((int)0xe0000203),
KeyDoesNotExist = unchecked((int)0xe0000204),
InvalidDevinstName = unchecked((int)0xe0000205),
InvalidClass = unchecked((int)0xe0000206),
DevinstAlreadyExists = unchecked((int)0xe0000207),
DevinfoNotRegistered = unchecked((int)0xe0000208),
InvalidRegProperty = unchecked((int)0xe0000209),
NoInf = unchecked((int)0xe000020a),
NoSuchHDevinst = unchecked((int)0xe000020b),
CantLoadClassIcon = unchecked((int)0xe000020c),
InvalidClassInstaller = unchecked((int)0xe000020d),
DiDoDefault = unchecked((int)0xe000020e),
DiNoFileCopy = unchecked((int)0xe000020f),
InvalidHwProfile = unchecked((int)0xe0000210),
NoDeviceSelected = unchecked((int)0xe0000211),
DevinfolistLocked = unchecked((int)0xe0000212),
DevinfodataLocked = unchecked((int)0xe0000213),
DiBadPath = unchecked((int)0xe0000214),
NoClassInstallParams = unchecked((int)0xe0000215),
FileQueueLocked = unchecked((int)0xe0000216),
BadServiceInstallSect = unchecked((int)0xe0000217),
NoClassDriverList = unchecked((int)0xe0000218),
NoAssociatedService = unchecked((int)0xe0000219),
NoDefaultDeviceInterface = unchecked((int)0xe000021a),
DeviceInterfaceActive = unchecked((int)0xe000021b),
DeviceInterfaceRemoved = unchecked((int)0xe000021c),
BadInterfaceInstallSect = unchecked((int)0xe000021d),
NoSuchInterfaceClass = unchecked((int)0xe000021e),
InvalidReferenceString = unchecked((int)0xe000021f),
InvalidMachineName = unchecked((int)0xe0000220),
RemoteCommFailure = unchecked((int)0xe0000221),
MachineUnavailable = unchecked((int)0xe0000222),
NoConfigMgrServices = unchecked((int)0xe0000223),
InvalidPropPageProvider = unchecked((int)0xe0000224),
NoSuchDeviceInterface = unchecked((int)0xe0000225),
DiPostProcessingRequired = unchecked((int)0xe0000226),
InvalidCOInstaller = unchecked((int)0xe0000227),
NoCompatDrivers = unchecked((int)0xe0000228),
NoDeviceIcon = unchecked((int)0xe0000229),
InvalidInfLogConfig = unchecked((int)0xe000022a),
DiDontInstall = unchecked((int)0xe000022b),
InvalidFilterDriver = unchecked((int)0xe000022c),
NonWindowsNTDriver = unchecked((int)0xe000022d),
NonWindowsDriver = unchecked((int)0xe000022e),
NoCatalogForOemInf = unchecked((int)0xe000022f),
DevInstallQueueNonNative = unchecked((int)0xe0000230),
NotDisableable = unchecked((int)0xe0000231),
CantRemoveDevinst = unchecked((int)0xe0000232),
InvalidTarget = unchecked((int)0xe0000233),
DriverNonNative = unchecked((int)0xe0000234),
InWow64 = unchecked((int)0xe0000235),
SetSystemRestorePoint = unchecked((int)0xe0000236),
IncorrectlyCopiedInf = unchecked((int)0xe0000237),
SceDisabled = unchecked((int)0xe0000238),
UnknownException = unchecked((int)0xe0000239),
PnpRegistryError = unchecked((int)0xe000023a),
RemoteRequestUnsupported = unchecked((int)0xe000023b),
NotAnInstalledOemInf = unchecked((int)0xe000023c),
InfInUseByDevices = unchecked((int)0xe000023d),
DiFunctionObsolete = unchecked((int)0xe000023e),
NoAuthenticodeCatalog = unchecked((int)0xe000023f),
AuthenticodeDisallowed = unchecked((int)0xe0000240),
AuthenticodeTrustedPublisher = unchecked((int)0xe0000241),
AuthenticodeTrustNotEstablished = unchecked((int)0xe0000242),
AuthenticodePublisherNotTrusted = unchecked((int)0xe0000243),
SignatureOSAttributeMismatch = unchecked((int)0xe0000244),
OnlyValidateViaAuthenticode = unchecked((int)0xe0000245)
}
[StructLayout(LayoutKind.Sequential)]
internal struct DeviceInfoData
{
public int Size;
public Guid ClassGuid;
public int DevInst;
public IntPtr Reserved;
}
[StructLayout(LayoutKind.Sequential)]
internal struct PropertyChangeParameters
{
public int Size;
// part of header. It's flattened out into 1 structure.
public DiFunction DiFunction;
public StateChangeAction StateChange;
public Scopes Scope;
public int HwProfile;
}
internal class NativeMethods
{
private const string setupapi = "setupapi.dll";
private NativeMethods()
{
}
[DllImport(setupapi, CallingConvention = CallingConvention.Winapi, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool SetupDiCallClassInstaller(DiFunction installFunction, SafeDeviceInfoSetHandle deviceInfoSet, [In()]
ref DeviceInfoData deviceInfoData);
[DllImport(setupapi, CallingConvention = CallingConvention.Winapi, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool SetupDiEnumDeviceInfo(SafeDeviceInfoSetHandle deviceInfoSet, int memberIndex, ref DeviceInfoData deviceInfoData);
[DllImport(setupapi, CallingConvention = CallingConvention.Winapi, CharSet = CharSet.Unicode, SetLastError = true)]
public static extern SafeDeviceInfoSetHandle SetupDiGetClassDevs([In()]
ref Guid classGuid, [MarshalAs(UnmanagedType.LPWStr)]
string enumerator, IntPtr hwndParent, SetupDiGetClassDevsFlags flags);
/*
[DllImport(setupapi, CallingConvention = CallingConvention.Winapi, CharSet = CharSet.Unicode, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool SetupDiGetDeviceInstanceId(SafeDeviceInfoSetHandle deviceInfoSet, [In()]
ref DeviceInfoData did, [MarshalAs(UnmanagedType.LPTStr)]
StringBuilder deviceInstanceId, int deviceInstanceIdSize, [Out()]
ref int requiredSize);
*/
[DllImport("setupapi.dll", SetLastError = true, CharSet = CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool SetupDiGetDeviceInstanceId(
IntPtr DeviceInfoSet,
ref DeviceInfoData did,
[MarshalAs(UnmanagedType.LPTStr)] StringBuilder DeviceInstanceId,
int DeviceInstanceIdSize,
out int RequiredSize
);
[SuppressUnmanagedCodeSecurity()]
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
[DllImport(setupapi, CallingConvention = CallingConvention.Winapi, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool SetupDiDestroyDeviceInfoList(IntPtr deviceInfoSet);
[DllImport(setupapi, CallingConvention = CallingConvention.Winapi, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool SetupDiSetClassInstallParams(SafeDeviceInfoSetHandle deviceInfoSet, [In()]
ref DeviceInfoData deviceInfoData, [In()]
ref PropertyChangeParameters classInstallParams, int classInstallParamsSize);
}
internal class SafeDeviceInfoSetHandle : SafeHandleZeroOrMinusOneIsInvalid
{
public SafeDeviceInfoSetHandle()
: base(true)
{
}
protected override bool ReleaseHandle()
{
return NativeMethods.SetupDiDestroyDeviceInfoList(this.handle);
}
}
public sealed class DeviceHelper
{
private DeviceHelper()
{
}
/// <summary>
/// Enable or disable a device.
/// </summary>
/// <param name="classGuid">The class guid of the device. Available in the device manager.</param>
/// <param name="instanceId">The device instance id of the device. Available in the device manager.</param>
/// <param name="enable">True to enable, False to disable.</param>
/// <remarks>Will throw an exception if the device is not Disableable.</remarks>
public static void SetDeviceEnabled(Guid classGuid, string instanceId, bool enable)
{
SafeDeviceInfoSetHandle diSetHandle = null;
try
{
// Get the handle to a device information set for all devices matching classGuid that are present on the
// system.
diSetHandle = NativeMethods.SetupDiGetClassDevs(ref classGuid, null, IntPtr.Zero, SetupDiGetClassDevsFlags.Present);
// Get the device information data for each matching device.
DeviceInfoData[] diData = GetDeviceInfoData(diSetHandle);
// Find the index of our instance. i.e. the touchpad mouse - I have 3 mice attached...
int index = GetIndexOfInstance(diSetHandle, diData, instanceId);
// Disable...
EnableDevice(diSetHandle, diData[index], enable);
}
finally
{
if (diSetHandle != null)
{
if (diSetHandle.IsClosed == false)
{
diSetHandle.Close();
}
diSetHandle.Dispose();
}
}
}
private static DeviceInfoData[] GetDeviceInfoData(SafeDeviceInfoSetHandle handle)
{
List<DeviceInfoData> data = new List<DeviceInfoData>();
DeviceInfoData did = new DeviceInfoData();
int didSize = Marshal.SizeOf(did);
did.Size = didSize;
int index = 0;
while (NativeMethods.SetupDiEnumDeviceInfo(handle, index, ref did))
{
data.Add(did);
index += 1;
did = new DeviceInfoData();
did.Size = didSize;
}
return data.ToArray();
}
// Find the index of the particular DeviceInfoData for the instanceId.
private static int GetIndexOfInstance(SafeDeviceInfoSetHandle handle, DeviceInfoData[] diData, string instanceId)
{
const int ERROR_INSUFFICIENT_BUFFER = 122;
for (int index = 0; index <= diData.Length - 1; index++)
{
StringBuilder sb = new StringBuilder(1);
int requiredSize = 0;
bool result = NativeMethods.SetupDiGetDeviceInstanceId(handle.DangerousGetHandle(), ref diData[index], sb, sb.Capacity, out requiredSize);
if (result == false && Marshal.GetLastWin32Error() == ERROR_INSUFFICIENT_BUFFER)
{
sb.Capacity = requiredSize;
result = NativeMethods.SetupDiGetDeviceInstanceId(handle.DangerousGetHandle(), ref diData[index], sb, sb.Capacity, out requiredSize);
}
if (result == false)
throw new Win32Exception();
if (instanceId.Equals(sb.ToString()))
{
return index;
}
}
// not found
return -1;
}
// enable/disable...
private static void EnableDevice(SafeDeviceInfoSetHandle handle, DeviceInfoData diData, bool enable)
{
PropertyChangeParameters @params = new PropertyChangeParameters();
// The size is just the size of the header, but we've flattened the structure.
// The header comprises the first two fields, both integer.
@params.Size = 8;
@params.DiFunction = DiFunction.PropertyChange;
@params.Scope = Scopes.Global;
if (enable)
{
@params.StateChange = StateChangeAction.Enable;
}
else
{
@params.StateChange = StateChangeAction.Disable;
}
bool result = NativeMethods.SetupDiSetClassInstallParams(handle, ref diData, ref @params, Marshal.SizeOf(@params));
if (result == false) throw new Win32Exception();
result = NativeMethods.SetupDiCallClassInstaller(DiFunction.PropertyChange, handle, ref diData);
if (result == false)
{
int err = Marshal.GetLastWin32Error();
if (err == (int)SetupApiError.NotDisableable)
throw new ArgumentException("Device can't be disabled (programmatically or in Device Manager).");
else if (err >= (int)SetupApiError.NoAssociatedClass && err <= (int)SetupApiError.OnlyValidateViaAuthenticode)
throw new Win32Exception("SetupAPI error: " + ((SetupApiError)err).ToString());
else
throw new Win32Exception();
}
}
}
}
Note that when you get an Index-Out-Of-Bounds exception on the line int index = GetIndexOfInstance(diSetHandle, diData, instanceId);, you might have used the wrong classGuid for the device or the wrong instanceId.
Also note that when you run this code on a 64-bit Windows platform, you should target the 64-bit platform when you build your application. Otherwise - i.e. when running your application as a 32-bit process on a 64-bit Windows platform - you will get an SetupAPI error InWow64 (ERROR_IN_WOW64).
When targetting a 64-bit Windows platform, you might also have to make changes to other parts of your application, e.g. when doing pointer arithmetic, in order to prevent overflows.
One way might be to use the Windows Management Instrumentation layer. There seems to be a few device related classes defined in this layer.