Multiple combo boxes bound to same source with conditional visibility on items
<p>Unlike many questions related to this, I'm not having an issue with all combo box values being changed at when changing one combo box selection.</p>

<p>My problem is that I want to change the visibility of certain items when they are selected in the other list. I have two input port combo boxes and when I select port 5, say, on the first one, I want port 5 to not appear in the drop down for the second combo box.</p>

<p>I've tried this solution <a href="https://stackoverflow.com/questions/13557942/how-to-set-combox-item-visibility">How to set combox item visibility?</a> as it looked very promising but it won't let me cast from <code>string</code> to <code>ComboBoxItem</code> in the code-behind.</p>

<p>What else am I to do? I thought of creating a style in the XAML itself, but I can't quite figure out the conditions to use within the XAML and can't seem to find any topics over it. Lastly, I also have conditions in the setters for my input properties to check that the value the port is being set to is not the same as the other port, but it's not seeming to do anything for the view.</p>