How can I setup a .NET Custom Action within WiX 3.0?

Question

I need to setup a custom action within WiX 3.0. I have the following setup in my Windows application exe.

I have viewed the question at StackOverflow: Removing files when uninstalling Wix however I can't get this working with WiX 3.0. This seems to deal with InstallUtilLib.dll, however I can't work out how I call the custom action within my main Windows app executable.

Also, is there some method that I can use to manually invoke and test the OnBeforeUninstall function is working as expected?

Imports System.Configuration.Install.Installer
Imports System.IO

Public Class CustomInstaller
    Inherits Configuration.Install.Installer

    Protected Overrides Sub OnBeforeUninstall(ByVal savedState As System.Collections.IDictionary)
        MyBase.OnBeforeUninstall(savedState)

        Try

    End Sub

End Class

Answer 1

InstallUtil is an ugly antipattern. If you need a managed CustomAction you should use WiX's DTF pattern. Also you should attempt to avoid CustomActions all together whenever native WiX/MSI functionality will handle your needs. Have you tried to use the RemoveFile element?