Fixing c#/VB project, turn on/off checkbox from multiple places

Hi, I have a Visual Studio solution that is logging numbers to a file. I want to turn on/off the logging via a checkbox from multiple places. It kind of works, I can turn it on/off, but in 1 xaml the checkbox does not update when I change it in another. I also want to turn on/off the logging from a VB project in the same solution. Should be real simple. I attached the code from the xaml where the checkbox works fine, so you can see the details. Thank you.