This is a transform designed to be used on a link between a component generating
filenames (ie. com.sas.io.FileList) and a component which uses filenames to access
data (ie. com.sas.visuals.ImageView). The transform checks to see if the filename
passed in is for a file. If it is, it returns the filename. Otherwise, it returns
null.
An example of using this is to link the selectedItem property of a TreeView containing
a FileList to the source property of an ImageView. To setup such a link you
would add code like the following: