FormController Events
The FormController object provides the following events.
Note: While using the
thiskeyword (for example,this.view) in a FormController event in order to point to the current controller, you must ensure that the function is not a fat arrow function. Because in fat arrow types of function declarations, thethiskeyword is taken from the parent scope and might not point to the current FormController. For more information on this limitation, click here.
Invoked when the Navigation object retrieves the model for the current FormController object.
Syntax
getModel();
Parameters
None.
Return Values
Returns the model object that is required for the form.
Remarks
Your app does not directly access the FormController object for a form. If your app needs the model associated with the FormController object, it can access the model by retrieving it through an instance of the Navigation object. This event handler retrieves the model that you want it to use for the form.
Example
getModel : function ()
{
var model = new CustomFormModel();
return model;
}
Called when the controller is ready to create the view.
Syntax
onCreateView();
Parameters
None.
Return Values
Returns either the file name of the form to use as the view or an instance of the form.
Remarks
Use this method to dynamically select which view to use for the controller when your app has more than one view for a controller. For more information, see Sharing Controllers Between Forms.
Example 1
onCreateView : function ()
{
return "ViewFileName.js");
}
Example 2
onCreateView : function ()
{
// Create an instance of the view to return or
// retrieve the instance from somewhere in your
// code where you have stored it. In this example,
// it's saved in a variable called newInstance.
return (viewInstance);
}
Triggered just before a form is destroyed.
Syntax
onDestroy();
Parameters
None.
Return Values
None
Remarks
Use this event callback handler function to perform cleanup tasks when a form is about to be destroyed.
Example
onDestroy : function ()
{
this.context = null;
this.model = null;
}
This event is invoked when you navigate from one form to another. This is a Form Controller event and is used only in VoltMX Reference Architecture-based projects.
Syntax
onNavigate(
context,
isBackNavigation)
Parameters
context [Object]
A JavaScript object that contains the data that the destination form requires after navigation.
isBackNavigation [Boolean]
This parameter determines whether you have clicked the back button or not. It has the value as true when you click the back button and false when you do not click the back button.
Read/Write
Read + Write
Remarks
To navigate from one form to another, you must create a Navigation Object. This object navigates to the destination form's controller. The form's controller in turn displays the view of the form.
This event is useful in the following scenarios:
- To prepare data that the destination form requires after the navigation.
- To pause the navigation if any asynchronous calls are in progress.
Note: The object that is sent as part of the onNavigate Event is accessible for all form lifecycle events.
Example
define({
onNavigate: function(context, isBackNavigation) {
this.context = context;
this.pauseNavigation();
voltmx.net.invokeServiceAsync(url, this.callback1);
},
callback1: function(result) {
this.resumeNavigation();
}
});
Platform Availability
Available on all platforms
Invoked while navigating to a new form the model to set the form's updated model object.
Syntax
setModel(
model);
Parameters
model
The model object for the new form.
Return Values
None.
Remarks
Use this event callback handler to set a model for the form being navigated to.
Example
setModel : function (model)
{
this.model = model;
}