Property MessageExpression

MessageExpression

Gets or sets an ArcadeExpression that controls the notification details when a Geotrigger is met.

Declaration

public ArcadeExpression MessageExpression { get; set; }

Property Value

Type	Description
ArcadeExpression	The ArcadeExpression for the Message.

Remarks

The expression uses the Arcade language to generate notification information that can be:

• a string literal that is the same for all notifications relating to this Geotrigger.
• information that is specific to the attributes of the fence and objects that met the Geotrigger.

The expression is evaluated whenever the Geotrigger condition is met, in order to populate the Message property. Display this message to alert the user that the Geotrigger condition has been met. Note that the expression cannot be changed when the GeotriggerMonitor is running.

For example, with a FenceGeotrigger, using the following expression:

  "You have " + $fencenotificationtype + " " + $fencefeature.area_name

returns the Message "You have entered Area A", where "area_name" is an attribute field on the FenceGeoElement.

Optionally, the expression can return extra properties in addition to the message. For example, it could produce another string, suitable for logging to a database. To supply additional properties, write an arcade expression that evaluates to a dictionary of key / value pairs:

• A value with the key "message" will be used to populate the Message property.
• A value with the key "actions" will populate the GeotriggerNotificationInfo actions property.
• Any additional key / value pairs are returned in the MessageProperties dictionary.

For example, this expression results in a Message of: "Hello world" and a GeotriggerNotificationInfo actions list of either "startTracking" or "stopTracking".

  var action = IIf($fencenotificationtype == 'enter', 'stopTracking', 'startTracking')
  return {
  'message': 'Hello world',
  'actions': [ action ]
  }

The ArcadeExpression must evaluate to either a string or a dictionary; see ReturnType. Note that this property is an ArcadeExpression object rather than a string.

This property may be null; if so, notifications sent by the geotrigger will pass a GeotriggerNotificationInfo with Message evaluated to an empty string and an empty MessageProperties dictionary.

For more information on the available profile variables and functions for creating the MessageExpression, see the "Geotrigger Notification" profile at Profiles.

Applies to

Platforms and versions

Target	Versions
.NET Standard 2.0	100.12 - 200.5
.NET	100.13 - 200.5
.NET Windows	100.13 - 200.5
.NET Android	200.0 - 200.5
.NET iOS	200.0 - 200.5
.NET Framework	100.12 - 200.5
Xamarin.Android	100.12 - 100.15
Xamarin.iOS	100.12 - 100.15
UWP	100.12 - 200.5