How to get unreal widget position if the widget is not rendering?

Development Programming & Scripting
1

I added a lot widgets into a verticalBox as child widgets. The verticalBox’s parent widget is a scrollbox. So it could get right position when I scroll the bar if the created widget is rendering in the scrollbar. But if not the position look like a cache position.

And this is the way I get the absolutePos with widgets.

if (Widget)
{
    const FGeometry& Geometry = Widget->GetCachedGeometry();
    FVector2D Pixel2D;
    FVector2D Viewport2D;
    USlateBlueprintLibrary::LocalToViewport(Widget, Geometry, LocalPos, Pixel2D, Viewport2D);
    // PosX, PosY is the output position
    PosX = Viewport2D.X;
    PosY = Viewport2D.Y;
}
2

After read the engine code, I found that SScrollBox::InternalScrollDescendantIntoView function would return the right position of the invisible widget.
So I clone this code and create a new function to return the position value.