Blocking Mouse Hook for a vb.net application when the task manager has focus.

Question

Blocking Mouse Hook for a vb.net application when the task manager has focus.

jacky Perpète 126

Hello,

For a VB.NET application with WPF, I'm using a transparent window that follows the movement of the mouse cursor on the screen.

This application uses the mouse hook to handle the move event.

This window represents a custom cursor.

This test application works correctly except on Windows applications like Task Manager or Device Manager.

When one of these windows gains focus, the mouse hook is disabled in my application.

How can I prevent this?

I've seen custom cursors using the same principle that don't have this problem.

I'm attaching my test program in VB under WPF.To attach it.

I changed the file extension from .zip to .txt.

To use it, you'll need to change the extension from .txt to .zip.

WpfCursorWindow.txt

TestHookMouse

Accepted answer

0 additional answers

Your answer

Answer 1

RLWA32 48,151

If you are signed-on as an account that is a member of the Administrators group then Task Manager will auto-elevate so it will run with a high integrity level. Your application runs at medium integrity so Windows built-in security measures prevent the low-level mouse hook from interacting with Task Manager.

You can work around this by making your application a UIAccess application. This is done by signing the application, installing it to a protected file system location and manifesting it with uiAccess=true. An alternative is to run the application with elevated privileges as Administrator though this is probably not what you would want. The screen capture isn't very good but it does demonstrate the solution works -

UIAccess

jacky Perpète 126 Reputation points

2025-04-20T13:07:04.4433333+00:00

Thank you for your solution.

I'll try to figure out how to transform my application into a UIACCESS application.

And how to sign my solution.

This program can be installed on other PCs.
RLWA32 48,151 Reputation points

2025-04-20T14:19:16.9366667+00:00

To sign an application that you distribute to users (other than yourself) you need a code-signing certificate that is purchased from a third party vendor. Such a certificate will chain back to a trusted root certificate. The signtool.exe utility (usually installed with various Microsoft SDKs) can be used to digitally sign your application with that certificate.

For test purposes you can create self-signed certificates that you use on your test systems. These would be of no use for applications distributed to other users since your self-signed certificates would not be trusted.

In Visual Studio you add an Application Manifest to your project. Then open the manifest file in the editor and set uiAccess setting to "true".

Installing to a secure file system location means folders located under "\Program Files', "\Program Files (x86)" or "\Windows\System32".

For example, Project ->Add New Item -

Set uiAccess to true -

Use a post-build event to sign your application -
jacky Perpète 126 Reputation points

2025-04-20T14:57:32.3733333+00:00

Thank you very much for your comment.

Your explanation of certification is clear and confirms my online research.

Share via

Blocking Mouse Hook for a vb.net application when the task manager has focus.

0 additional answers

Your answer