ISensor.RegisterForNotification()

Description:

The RegisterForNotification method registers the +client to receive data from one sensor channel.

This is an asynchronous method.

Syntax:

+ +

result = so.ISensor.RegisterForNotification(criteria, callback);

Arguments:

criteria:
+ +
This is an object that specifies the sensor channel to listen for data. +For more information about the object properties and how to define them, see +section Criteria for receiving sensor data.
+ +
callback:
+ +
The callback argument is the name of the method +that is executed when a RegisterForNotification call +has results or status information to return. You must define this method separately. +Follow the instructions in section Defining the callback handler for an asynchronous method to +define the callback method.
+ +

Return value:

The RegisterForNotification method returns an object +that contains the initial return value for the asynchronous call it started +(see the following table). The actual sensor data is returned by the callback method +in the ReturnValue property of its result object. The +returned data is described in section Returned sensor data.

+ + + + + + + + + + + + + + + + + + + + +

**Table:** Return value +properties for RegisterForNotification
+ Property +	+ Description +	+ Value +
+ `result.TransactionID` +	+ This is a number used as an identification to match transactions started +with the `RegisterForNotification` call to one or more +calls it generates to `callback`. +
+ `result.ErrorCode` +	+ This is a number that specifies a predefined error code. +	+ See Service API error codes. +
+ `result.ErrorMessage` +	+ This is a text string that describes the error. +	+ See Sensor Service API error messages. +

Remarks:

RegisterForNotification retrieves sensor +data until cancelled with Cancel.
Invoking the same call on the same sensor channel from the +same user without cancelling the previous RegisterForNotification request +results in an error, since the channel is already listening on the pre-registered +notifications.

Example code:

For the complete source of a sample widget +that demonstrates how to use this Service API, see the +full example.

+ + +