Count files inside a comic book

Hello
I want to count files inside comic book (who are basically zip or rar file renamed)
I've noticed that, if I had a column under general\number total of files (I guess it's something like that, I have a french version), DOPUS knows how to count the files.
image
So I write this:

@script VBScript
Option Explicit
dim cmd, selitem

Function OnClick(ByRef clickData)
	DOpus.ClearOutput

	' ---------------------------------------------------------
	Set cmd = clickData.func.command
	cmd.deselect = false ' Prevent automatic deselection

	' ---------------------------------------------------------
	If clickData.func.sourcetab.selected.count = 0 Then
		DOpus.Output "  (none)"
	Else
		For Each selItem in clickData.func.sourcetab.selected
				 dopus.output "nombre de fichiers " & selitem.metadata.other.filecounttotal
		Next
	End If
	' ---------------------------------------------------------

	' ---------------------------------------------------------
End Function

The problem is that I've got a number only if I had previously added the column.
How can I force my script to have the data ?

You can calculate the number of files below an archive in the script without relying on file display columns:

var filePath = "C:\\My Test Folder\\Fo.ols.cbz";
var fileCount = FileCountRecursive(filePath);
DOpus.Output("File count = " + fileCount);

function FileCountRecursive(filePath) {
	var fileCount = 0;
	var folderEnum = DOpus.FSUtil.ReadDir(filePath, "r");
	while (!folderEnum.complete) {
		var folderItem = folderEnum.Next;
		if (!folderItem.is_dir) {
			++fileCount;
		}
	}
	return fileCount;
}

Thanks you, I translated it in Vbscript and this is working

@script VBScript
Option Explicit
dim cmd, selitem

Function OnClick(ByRef clickData)
	DOpus.ClearOutput

	' ---------------------------------------------------------
	Set cmd = clickData.func.command
	cmd.deselect = false ' Prevent automatic deselection

	' ---------------------------------------------------------
	If clickData.func.sourcetab.selected.count = 0 Then
		DOpus.Output "  (none)"
	Else
		For Each selItem in clickData.func.sourcetab.selected
				 dopus.output "nom du fichier " & selitem & " contient " & FileCountRecursive(selitem)
		Next
	End If
	' ---------------------------------------------------------

	' ---------------------------------------------------------
End Function


function FileCountRecursive(filePath) 
  dim filecount:	dim folderEnum: 	dim folderItem
  Set folderEnum = DOpus.FSUtil.ReadDir(filePath,"r")
  Do while (not folderEnum.complete)
		set folderItem = folderEnum.Next
		if not(folderItem.is_dir) then
			fileCount=filecount+1
		end if
  loop
  FileCountRecursive= fileCount
End function