Change the available records is a Tree selector on the SS Portal

On the self service portal, when you open the Catalogue, you can select a Category which populates from the Item Sales Categories screen on the main site.

We don’t want to display ALL categories.  I added a custom field to the screen to indicate that we want to show the selected category on the portal.

I think I found where the Categories selector is populated on the SSP.

public class PXSelectCategoriesTree : PXSelectBase<INCategory>
{
    public PXSelectCategoriesTree(PXGraph graph)
    {
        this.View = CreateView(graph, new PXSelectDelegate<int?>(categories));
    }

    public PXSelectCategoriesTree(PXGraph graph, Delegate handler)
	{
		this.View = CreateView(graph, handler);
	}

    private PXView CreateView(PXGraph graph, Delegate handler)
    {
        return new PXView(graph, false,
			new Select<INCategory,
				Where<INCategory.parentID, Equal<Argument<int?>>>,
				OrderBy<Asc<INCategory.sortOrder>>>(),
            handler);
    }

    internal IEnumerable categories([PXInt] int? CategoryID)
    {
        if (CategoryID == null)
            CategoryID = 0;

		foreach (var ret in PXSelect<INCategory,
			Where<INCategory.parentID, Equal<Required<INCategory.parentID>>>,
			OrderBy<Asc<INCategory.sortOrder>>>
			.Select(new PXGraph(), CategoryID))
        {

//CHECK HERE IF I SHOULD YIELD THE RECORD

            yield return ret;
        }
    }
}

I want to be able to add a restriction in the internal IEnumerable categories([PXInt] int? CategoryID) to allow me to check if the category is designated to Display on Portal from my custom field.

There aren’t many lines of code here, so maybe I can just overwrite the entire class???  

I tried to the code below, but the code doesn’t even fire in debug mode.  I was hoping there was just a simple way to “reject” the category as it is being selected, but I don’t think this is going to work, ever.

I’m showing this code just to prove I tried something…  :-)

	protected virtual void InventoryLineFilter_RowSelecting(PXCache cache, PXRowSelectingEventArgs e, PXRowSelecting InvokeBaseHandler)
	{
		if (InvokeBaseHandler != null)
			InvokeBaseHandler(cache, e);
		var row = (InventoryLineFilter)e.Row;
		if (row == null) return;

		InventoryLineFilter filter = Base.Filter.Current;

		if (filter == null) return;

		INCategory category = SelectFrom<INCategory>.Where<INCategory.categoryID.IsEqual<@P.AsInt>>
			.View.Select(Base, row.CategoryID);

		CummingsSSPINCategoryExt ext = category.GetExtension<CummingsSSPINCategoryExt>();
		if (ext == null) return;

		if (ext.UsrDisplayOnPortal != true)
		{
			e.Cancel = true;
		}
	}

Not only do I need to restrict the Category selector, I will also need to restrict the default records showing in the grid when the screen is first opened.  By default, it lists everything.   Baby steps.