RecordSet.addView( )

RecordSet.addView( ) Method

Flash 6

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monitors RecordSet activity by watching certain events

   myRecordSet   .addView(   object   ) 

Arguments

object

An object with a method named modelChanged( ) that is notified of changes to the recordset.

Description

The addView( ) method allows you to specify an object to be notified whenever changes occur to a RecordSet object. This allows you to perform certain actions in response to those changes. For example, if you want to implement a recordset logging feature, you can use an object that displays information about the recordset in the Output window whenever the recordset changes.

Typically addView( ) is used during debugging to verify that certain events happened . Chapter 4 discusses the method in detail, and Example 4-3 creates a RecordSetDebug.as file containing methods to view recordsets for debugging purposes.

Table 15-3 shows the event information sent to the object specified in the addView( ) method. It also indicates which operations generate each event.

Table 15-3. Events tracked in the addView( ) method

Event	Information object returned	Occurs when
addItem( ) and addItemAt( ) methods	{event:"addRows", firstRow: n , lastRow: nn }	Row numbers between n and nn are added
onResult( ) method of responder object	{event:"allRows"}	The recordset is fully populated from the server
removeAll( ) , removeItemAt( )	{event:"deleteRows", firstRow: n , lastRow: nn }	Row numbers between n and nn are deleted
onResult( ) method of responder object	{event:"fetchrows", firstRow: n , lastRow: nn }	Row numbers between n and nn are requested from the server, but have not yet arrived
sort ( ) and sortItemsBy( ) methods	{event: "sort"}	A recordset is sorted
Any change in the RecordSet	{event:"updateAll"}	A recordset changes in any way
replaceItemAt( ) , setField( )	{event:"updateRows", firstRow: n , lastRow: nn }	Row numbers between n and nn change in any way

Example

First, create an ActionScript object that defines a modelChanged( ) method, like this:

 var myObject = new Object( ); myObject.prototype.modelChanged = function (myInformationObject) {   trace(myInformationObject.event); }; 

Then call addView( ) , passing myObject as a parameter:

 myRecordset_rs.addView(myObject); 

This causes myObject 's modelChanged( ) method to be invoked whenever the contents of myRecordset_rs change. When an event triggers the modelChanged( ) method, it receives an information object ( myInformationObject ) as a parameter. This information object contains an event property, indicating the type of change that occurred to the recordset, as shown in Table 15-3. Some objects passed to modelChanged( ) also contain firstRow and lastRow properties indicating the range or record numbers affected.

Here is a fleshed-out example that displays a message in the Output window whenever the recordset is sorted:

 #include "RecordSet.as" var myRecordset_rs = new RecordSet(["First","Last","Email"]); // Create the generic object var myObject = new Object( ); // Add a   modelChanged( )   event handler the object myObject.modelChanged = function (myInformationObject) {   if (myInformationObject.event == "sort") {     trace("RecordSet was sorted");   } }; // Call   addView( )   to set up the callback function (   myObject.modelChanged   ) myRecordset_rs.addView(myObject); myRecordset_rs.addItem({First:"Tom",Last:"Muck",Email:"[e-mail]"}); myRecordset_rs.addItem({First:"Jack",Last:"Splat",Email:"[e-mail]"}); // Sort the recordset, triggering the   modelChanged( )   method myRecordset_rs.sortItemsBy("First"); 

At this point, the Output window should display "RecordSet was sorted."

See Also

Chapter 4 ( especially Example 4-3)