The secret of Multirow Variable Set – ServiceNow MRVS on Change (Part 2)

[Cuong Phan]

The secret of Multirow Variable Set – ServiceNow MRVS on Change

Reference: Article Link

In previous part, we have gone through the basic configuration for Multirow Variable Set (MRVS). In this article, I will cover the secret to catch ServiceNow MRVS on Change.

First thing first, what is the requirement?

Situation: We want to show/hide some field whenever one row is inserted in MRVS and hide that field if no rows.

Show/Hide Fields when insert/update MRVS

HOW TO DO THAT?

Step 1: Create a custom/macro widget to store your logic script (which is a widget)

In your catalog item/ record producer, create a new variable with type of “Custom” (new name on Quebec or Macro in previous releases.

Create CUSTOM Variable with logic stored in widget

Step 2: Create a custom widget that stores logic on client side part

The reason we don’t use ‘CLIENT SCRIPT’ since ServiceNow Client Script does not recognize any change of MRVS. Remember to include “$scope” api to use the function $watch to recognize any change made from MRVS.

api.controller=function($scope) {
	/* widget controller */
	var c = this;
	var mrvsName = 'multirow_variable_set_title';
	
	$scope.$watch(function() {
		return $scope.page.g_form.getValue(mrvsName);
	}, function(value) {
		// Action when change
		g_form = $scope.page.g_form;
		
		if (value) {
			g_form.setDisplay('json_output',true); // Field name needs to show/hide
		} else {
			g_form.setDisplay('json_output',false);
		}
	});
};

What did “Value” object return?

The value of this kind of function returns the value of MRVS (g_form.getValue(mrvsName)). They are stored as a JSON object. So in order to handle it easily, we can use:

JSON.parse(value)

This way will convert to array object that we can manage to control easier

To Sum Up,

We have gone through the way to catch change event from a MRVS, but there is still more tricks we can play with

TO BE CONTINUE…

[Kieran Anson]

As an alternative, you can do this in client scripts as follows (no custom widget necessary).

Save g_form as a window variable

On the catalog item, add an onLoad client script (that has isolated set to false) with the following:

function onLoad() {
this.my_g_form = g_form;
}

Use an onSubmit script within the MRVS

When a new row is added to the MRVS, any onSubmit client scripts are executed.

function onSubmit() {
   
	if(this.my_g_form){

		this.my_g_form.setDisplay('mrvs_label', true);
	}
}

Backend & Service Portal Submit

The above is intended for service portal, the functionality within the backend is actually easier and only requires the MRVS script as the g_form object is available.

function onSubmit() {

	//Run Desktop first
	if(parent.g_form){
		parent.g_form.setDisplay('mrvs_label', true);
	}

	//Run Service Portal (if g_form has been declared by cat_item client script)
	if(this.my_g_form){
		this.my_g_form.setDisplay('mrvs_label', true);
	}
}

[Diogo Figueira]

Hey Kieran.

Your solution is cool but doesn't cover a very important thing. It will not trigger if you delete a row/Delete all rows.

If you are doing something like the sum of a field that is within the MRVS this will not work if a row is removed. For that, Cuong's solution is better

[Sandesh9]

Hello Cuong,

I want to get the row object value which is removed from the mrvs. Any way to do that? for instance i only want to populate the multi line variable with the rows that are removed from mrvs?

Any help is appreciated.

Thanks,

Sandesh

[Ruchi Kumari1]

@Sandesh9 Did you get a solution to this ?

[Colleen]

Another widget-free alternative.

The MRVS triggers the following Angular events (should be self-explanatory):

• $sp.sc_multi_row_active_row.add
• $sp.sc_multi_row_active_row.update
• $sp.sc_multi_row_active_row.cancel

You can set up an event handler in a regular onLoad catalog client script.  For example:

function onLoad() {
	var $rootScope = (0, eval)('this').angular.element('main').injector().get('$rootScope');   

	$rootScope.$on('$sp.sc_multi_row_active_row.update', function(evt, data) {
		alert('MRVS change');
	});
}

Unfortunately, I've not been able to identify an event that is triggered when a row is deleted. 

[Colleen]

Update to widget-free alternative, which works when MRVS record is added, updated or deleted.

Implement $rootScope.$watch in the catalog onLoad client script.

function onLoad() {
	var $rootScope = (0, eval)('this').angular.element('main').injector().get('$rootScope');   

	$rootScope.$watch(
		function() {			
			try {
				var length = (
					g_form.getValue('mrvs')!='' ? 
					JSON.parse(g_form.getValue('mrvs')).length : 
					0
				);
				return length;
			} catch (ex) {
				return 0;
			}

		}, 
		function() { 
// do something with MRVS data
               }
	);
}