Beside that I inserted a checkbox in my screen. Everytime the user clicks the checkbox I want to add a another filter to my gallery: Status.Value=”Archiv” (Status is as well a choice column, and one value of the choices is “Archiv”). The filter disappears of course after the user unchecks the checkbox.
There are of course many ways to do this, however this is how I would do it easily - check for the status of the checkbox before the filter is actioned, so put all of the above in your items property and change the name to match your checkbox control name.
If you have any issues when implementing the above please feel free to ask for help,