How Can I Programmatically Enable or Disable Devices in Win32, and What are the Limitations?

Programmatic Device Management in Win32

Enabling/Disabling Devices

Windows provides APIs in the SetupDi family for managing devices programmatically, including enabling and disabling them. However, not all devices support being disabled this way.

Mouse Device Issue

In the case of mouse devices, the default PS/2-compatible mouse driver does not support disablement via SetupDi APIs due to concerns about destabilizing the hardware when hot-detaching actual old mice using PS/2 connectors.

Checking for Disable Capability

To determine if a device can be disabled using SetupDi APIs, check the Device Manager for a "Disable" option. If present, you can use the SetupDi APIs. If absent, you're left with IOCTL communication options.

Code for Disabling a Mouse Device

If your mouse driver supports disablement via SetupDi APIs, the following code snippet demonstrates how to disable and re-enable it using C# and P/Invoke:

public static void EnableMouse(bool enable)
{
    Guid mouseGuid = new Guid("{4d36e96f-e325-11ce-bfc1-08002be10318}");
    string instancePath = @"ACPI\PNP0F03&3688D3F&0";
    DeviceHelper.SetDeviceEnabled(mouseGuid, instancePath, enable);
}

Using the DeviceHelper Library

To simplify the task, you can use the DeviceHelper library from the provided code block. It exposes a SetDeviceEnabled method that takes as input the class GUID, instance ID, and enable/disable flag.

Constraints

• Note that IndexOutOfRangeException may occur when using GetIndexOfInstance if the class GUID or instance ID is incorrect.
• To avoid SetupAPI error "InWow64," ensure that your application targets the 64-bit platform on 64-bit Windows.
• Additionally, consider potential pointer arithmetic overflows in your 64-bit application.

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