Catalog Ui Policy- Make Child field visible and mandatory only when the Parent selected has children

[VernYerem]

In our location table we have Buildings and Floors. Buildings are parents to Floors. Some of our buildings have no child floors.

I'd like to make a catalog UI Policy to show the field "Floor" and make it mandatory only when the field "Building" gets a referenced values that actually has floors.

"When to apply" is easy, when Building=anything. I created the script to fire when this condition is met, but I get Java errors on the form when testing.

function onCondition() {
var floors = new GlideRecord("cmn_location"); //Get locations
var buildingSID = g_form.getValue('scvar_building'); //Get selected bulding's sysID
floors.addEncodedQuery('parent.sys_id='+buildingSID); //Filter for items with a parent of the selected building
floors.query();

if (floors.hasNext()) { //Check to see if query resulted in any items
    g_form.setDisplay('scvar_floor', true); //Show Floor
    g_form.setMandatory('scvar_floor', true); //Make Floor Mandatory
	} 
else {	//Else if nothing has a parent of the selected building
    g_form.setDisplay('scvar_floor', false); //Hide Floor
    g_form.setMandatory('scvar_floor', false);	//Make Floor Optional
	}
}

I haven't done a ton of scripting on UI Policies, feels like im missing something simple. 

[VernYerem]

Not a good idea especially since it doesn't work in this case lol. Reading up on Glide Ajax now, seems pretty straight forward.

[jcmings · Accepted solution]

Since a UI Policy script runs on the client-side, it can't execute something like a GlideRecord query (since that's server-side code). If you want to run this check, you'll need to use GlideAjax and contact a script include, passing through the sys_id of the building. Your response from the script include will dictate what you do in the client script (e.g. you would change the floors.hasNext() to something like response == 'success' in your if statement).

If you need help getting started with GlideAjax, check out this comment I left yesterday. You'll have to shift the code a little bit, but the principle is the same.

I believe you'll also want to shift this all to a onChange and/or onLoad client script rather than using a UI Policy. This way, the system can adjust if the selected Building changes. 

[VernYerem]

This is what I worked out, seems to work alright. 

Script Include:

var DoesParentLocationHaveChildScriptInclude = Class.create();
DoesParentLocationHaveChildScriptInclude.prototype = Object.extendsObject(AbstractAjaxProcessor, {
    DoesParentLocationHaveChildFunction: function() {
        var ParentID = this.getParameter('sysparm_parent');

        var gr = new GlideRecord('cmn_location');
        gr.addEncodedQuery('parent.sys_id=' + ParentID); 
        gr.query();

        if (gr.next()) {
            return 'true'; 
        } else {
            return 'false';
        }
    }
});

 
Catalog Client Script:

function onChange(control, oldValue, newValue, isLoading) {
    if (isLoading || newValue == '') {
        return;
    }
    var buildingSID = g_form.getValue('scvar_building');
    var ga = new GlideAjax("DoesParentLocationHaveChildScriptInclude"); 
    ga.addParam("sysparm_name", 'DoesParentLocationHaveChildFunction'); 
    ga.addParam("sysparm_parent", buildingSID);
    ga.getXML(result);
}

function result(response) {
	var answer = response.responseXML.documentElement.getAttribute("answer");
    if (answer == "true") {
    g_form.setDisplay('scvar_floor', true);
    g_form.setMandatory('scvar_floor', true);
} if(answer == "false"){
	g_form.setMandatory('scvar_floor', false);
    g_form.setDisplay('scvar_floor', false);
}
}

If you see anything that can be improved upon, let me know!

[jcmings]

Nice! Glad it works and thanks for sharing your code. The only thing I can think to change--and it's very minor--is to use newValue instead of doing the g_form.getValue (I am assuming that your onChange field is scvar_building). 

So you'd pass in newValue as the param instead of buildingSID (and then won't need the variable declaration at all).

ga.addParam("sysparm_parent", newValue);