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Using nonintrusive notifications in the User Interface

  • Articolo

Notifications provide a programmatic way to send nonintrusive information to the User Interface (UI) in the Web client. Notifications differ from messages that are initiated by the Message method. Messages are modal, which means users are typically required to address the message and take some form of corrective action before they continue working. Notifications, however, are nonmodal. Their purpose is to give users information about a current situation, but they don't require any immediate action or block users from continuing with their current task. For example, you could have a notification that a customer's credit limit is exceeded.

Notifications in the UI

In the UI, notifications appear in the Notification bar (similar to validation errors) at the top of the page on which a user is currently working. The user can then choose to dismiss the notification, which clears it. Or, if actions are defined on notification, the user can choose one of the actions.

  • There can be multiple notifications. The notifications appear in chronological order from top to bottom.
  • Notifications remain during the page instance or until the user dismisses them or takes action on them.
  • Notifications that are defined on subpages, for example in parts and FactBoxes, appear in the same Notification bar.
  • Validation errors on the page will be shown first.

Adding code to send notifications to users

By using the Notification and NotificationScope data types and methods in AL, you can add code to send notifications to users. The following table provides an overview of the available methods. The sections that follow provide additional information about how to create notifications.

Method Description
Message Specifies the content of the notification that appears in the UI.
Scope Specifies the scope in which the notification appears.
Send Sends the notification to be displayed by the client.
AddAction Adds an action on the notification.
SetData Sets a data property value for the notification
GetData Gets a data property value from the notification.
Recall Recalls a sent notification.

Creating and sending a notification

You create a notification by using the Message and Send methods. The Message method defines the message part of the notification. When the Send method is called, the notification is sent to the client and content of the message is displayed.

MyNotification.Message := 'This is a notification';
MyNotification.Send();

The Send method call should be the last statement in the notification code, after any AddAction or SetData method calls for the notification instance.

Defining the notification scope

The scope determines where the notification is broadcast in the client. There are two different scopes: LocalScope and GlobalScope.

  • A LocalScope notification appears in context of the user's current task, that is, on the page, the user is currently working on. LocalScope is the default.

  • A GlobalScope notification isn't directly related to the current task, and will appear regardless of which page the user is viewing.

    Note

    GlobalScope is currently not supported. This will be implemented in a future release.

The following code creates a notification in the LocalScope:

MyNotification.Message := 'This is a notification';
MyNotification.Scope := NotificationScope::LocalScope;
MyNotification.Send();

Adding actions on a notification

You add actions on notifications by using the AddAction method. This method provides a way for you to create interactive notifications. By default, users have the option to dismiss the notifications. However, there might be cases where you want to provide users with different actions that they can take to address the notification, like opening an associated page for modifying data.

Conceptually, a notification action calls a method in a specified codeunit, passing the notification object in the call. The method includes the business logic for handling the action.

MyNotification.Message := 'This is a notification';
MyNotification.Scope := NotificationScope::LocalScope;
MyNotification.AddAction('Action 1',Codeunit::"Action Handler",'RunAction1');
MyNotification.AddAction('Action 2',Codeunit::"Action Handler",'RunAction2');
MyNotification.Send();

The basic steps for adding an action are as follows:

  1. Create a global method in a new or existing codeunit. The method must have a Notification data type parameter for receiving the notification object.
  2. Add AL code to the method for handling the action.
  3. Specify the codeunit and method in the AddAction method call.

Important

You can have more than one action on a notification. A LocalScope notification can have up to 3 actions. A GlobalScope notification can have up to 2 actions.

Sending data with a notification

You use the SetData and GetData methods to add data to a notification, which is typically needed when actions are invoked. The SetData method sets, or adds, data to the notification. The data is defined as text in a key-value pair. With the GetData method, you can then retrieve the data again.

The following code sets data for a notification:

MyNotification.Message := 'This is a notification';
MyNotification.Scope := NotificationScope::LocalScope;
MyNotification.SetData('Created',Format(CurrentDateTime,0,9));
MyNotification.SetData('ID',Format(CreateGuid(),0,9));
MyNotification.AddAction('Action 1',Codeunit::"Action Handler",'RunAction1');
MyNotification.AddAction('Action 2',Codeunit::"Action Handler",'RunAction2');
MyNotification.Send();

The following code gets the data for a notification:

DataValue := MyNotification.GetData('Created');
DataValue := MyNotification.GetData('ID');

Example

This simple example illustrates how notifications work and provides some insight into how you can use them. This example extends page 42 Sales Order of the CRONUS International Ltd. demonstration database according to the following:

  • The code compares a customer's balance with their credit limit. If the balance exceeds the credit limit, a notification is sent to the client.
  • The notification includes an action, which has the caption Change credit limit, that opens page 21 Customer Card. This enables the user to increase the credit limit.

To complete the example, follow these steps:

  1. Create a page extension object that extends page 42 Sales Order, and add the notification code on the OnOpenPage trigger.

    pageextension 50100 CreditBalanceNotification extends "Sales Order"
{

    trigger OnOpenPage()
    var
        Customer: Record Customer;
        CreditBalanceNotification: Notification;
        OpenCustomer: Text;
        Text003: Label 'The current balance exceeds the credit limit.';
        Text004: Label 'Change credit limit';
    begin
        Customer.Get("Sell-to Customer No.");
        if Customer."Balance (LCY)" > Customer."Credit Limit (LCY)" then begin
            //Create the notification
            CreditBalanceNotification.Message(Text003);
            CreditBalanceNotification.Scope := NotificationScope::LocalScope;
            //Add a data property for the customer number
            CreditBalanceNotification.SetData('CustNumber', Customer."No.");
            //Add an action that calls the ActionHandler codeunit, which you define in the next step.
            CreditBalanceNotification.AddAction(Text004, Codeunit::"ActionHandler", 'OpenCustomer');
            //Send the notification to the client.
            CreditBalanceNotification.Send();
        end;
    end;
}

  2. Create a codeunit called ActionHandler for handling the notification action. Add a global method called OpenCustomer that has a Notification data type parameter called CreditBalanceNotification for receiving the Notification object, and include the following code on the method:

    codeunit 50100 ActionHandler
{
    trigger OnRun()
    begin

    end;

    procedure OpenCustomer(CreditBalanceNotification: Notification)
    var
        CustNumber: Text;
        CustNo: Text;
        CustRec: Record Customer;
        CustPage: Page "Customer Card";
    begin
        //Get the customer number data from the SetData() call.
        CustNo := CreditBalanceNotification.GetData('CustNumber');
        // Open the Customer Card page for the customer.
        if CustRec.Get(CustNo) then begin
            CustPage.SetRecord(CustRec);
            CustPage.Run();
        end else begin
            Error('Could not find Customer: ' + CustNo);
        end;
    end;
}

Notification data type
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