Add a custom action on uninstall in Visual Studio 2017 setup project

Question

I have a C# application (winforms) and I'm trying to create a setup project for it, with the following customization: when the user tries to uninstall the application, I want to show a simple dialog with 2 textboxes (email and password) and one button. When the user presses the button, I want to make a request with those credentials and, if they are valid, I want to uninstall the app.

Now, I installed this extension for Visual Studio 2017 that gives me the Setup Project template.

I know that I have to deal with Custom Actions. I actually reached that screen:

But when I click on Add Custom Action, it wants me to upload a script or an executable file.

My problem is: what kind of executable / script do I have to put there? There is a special language built for this installer? Or I can just write C#?

I haven't found any kind of updated documentation on this topic except this one that works for Visual Studio 2010, but I need it for Visual Studio 2017.

Thank you respectfully.

Answer 1

This item template is available in 2017 also.

Create a separate Library project. Add there a new installer item and continue as it is said in the manual you've found