How to pass additional custom parameters in Form call?

Hi Community,

I want to launch a custom Form from an CommandBarMenu CUI event. Users can select multiple items in the grid and then click the CUI button. Then a form shall open up in which users can do certain operations with the selected items.

I want to pass the id´s of the selected items to the launched Forms. But I right now didn´t find an elegant way to pass the idlist or multiple items. I right now create a temporary item, but I am not very happy with the solution. I somehow think that passing custom paramters to Forms should be possible. I just don´t know how.

Does anyone of you know a solution? My main problem is not the actual passing of the custom parameters. But I don´t know how to retrive it later. 

Here´s my current code;

var idlist = options.selectedRowsIds;
var inn = new Innovator();

// Create temporary item to pass idlist (workaround!)
var tempItem = inn.newItem("Part");
tempItem.setProperty("_idlist",idlist);

// Launch Form
var topWnd = aras.getMostTopWindowWithAras(window);
topWnd = topWnd.main || topWnd;

var params = {
title: 'do something',
item: tempItem,
formId: "9336D7E4DD244391AEC9593DD8A5D85B"'
aras: aras,
//innovator: this.getInnovator(),
dialogWidth: 1200, // set width int
dialogHeight: 600, // set height int
content: 'ShowFormAsADialog.html',
idlist: idlist <<<<<<<<<---------------------------------------- // is it somehow possible to pass custom parameters with the form to avoid the tempItem? And how to I get it?

};

Thanks for any ideas!

Angela