Nov 13, 2006 - Dynamic DataGrid columns
Example of how to dynamically create DataGridColumns

A completely dynamic DataGrid example.

This example uses the xml from the Flexstore example.  It examines the first product node and uses that to create the definitions for the  columns.  There is some example logic to change the columns properties.

It then instantiates the GataGrid and its columns array, assigns the properties, and then the dataProvider, and then adds the dataGrid to the application container.

The example is fully self-contained, since a portion of the catalog.xml file is included in the mxml.

Tracy Spratt

<?xml version="1.0" encoding="utf-8"?>
<!-- This example uses the dataProvider to build the dataGrid columns dynamically -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical"
    creationComplete="initApp()">
<mx:Script><![CDATA[
  import mx.controls.dataGridClasses.DataGridColumn;
  import mx.controls.DataGrid;

  import mx.collections.XMLListCollection;
  import mx.controls.Alert;
 
  [Bindable]
 private var _xlcCatalog:XMLListCollection;    //the dataProvider for the DG
 
 //run by creationComplete
 public function initApp():void
 {
    _xlcCatalog = new XMLListCollection(xmlCatalog.product);  //wrap the XML product nodes in an XMLListCollection
    buildDG();                                                //creates the dataGrid
 }//initApp
 
 private function buildDG():void
  {
    var aColumnDef:Array = getColumnDefArray();                  //returns a noraml array of objects that specify DtaGridColumn properties
    var oColumnDef:Object;
    var dg:DataGrid = new DataGrid;                              //instantiate a new DataGrid
    var dgc:DataGridColumn;
    var aColumnsNew:Array = dg.columns
    var iTotalDGWidth:int = 0;
    for (var i:int=0;i<aColumnDef.length;i++)  {                  //loop over the column definition array
      oColumnDef = aColumnDef[i];
      dgc = new DataGridColumn();                                  //instantiate a new DataGridColumn
      dgc.dataField = oColumnDef.dataField;                        //start setting the properties from the column def array
      dgc.width = oColumnDef.width;
      iTotalDGWidth += dgc.width;                                  //add up the column widths
      dgc.editable = oColumnDef.editable;
      dgc.sortable = oColumnDef.sortable
      dgc.visible = oColumnDef.visible;
      dgc.wordWrap = oColumnDef.wordWrap;
      aColumnsNew.push(dgc)                                        //push the new dataGridColumn onto the array
    }
   
    dg.columns = aColumnsNew;                                      //assign the array back to the dtaGrid
    dg.editable = true;
    dg.width = iTotalDGWidth;
    dg.dataProvider = _xlcCatalog;                                 //set the dataProvider 
    this.addChild(dg);                                             //add the dataGrid to the application
  }//buildDG
 
 //uses the first product node to define the columns
 private function getColumnDefArray():Array
 {
    //Alert.show("colcount:" + xmlCatalog.toXMLString());
    var aColumns:Array = new Array();
    var node0:XML = xmlCatalog.product[0];                          //get the first "product" node
    var xlColumns:XMLList = node0.children();                        //get its child nodes (columns) as an XMLList
    var xmlColumn:XML
    var oColumnDef:Object;
    for (var i:int=0;i<xlColumns.length();i++)  {                    //loop over the xmlList
      xmlColumn = xlColumns[i];
      oColumnDef = new Object();
      oColumnDef.dataField = xmlColumn.localName();                  //make the dataField be the node name
      switch (oColumnDef.dataField)  {                              //conditional column property logic
        case "name":
          oColumnDef.width = 80;
          oColumnDef.sortable = false;
          oColumnDef.visible = true;
          oColumnDef.editable = false;
          oColumnDef.wordWrap = false;        
          break;
        case "description":
          oColumnDef.width = 200;
          oColumnDef.sortable = false;
          oColumnDef.visible = true;
          oColumnDef.editable = false;
          oColumnDef.wordWrap = true;        
          break;
        case "price":
          oColumnDef.width = 40;
          oColumnDef.sortable = true;
          oColumnDef.visible = true;
          oColumnDef.editable = true;
          oColumnDef.wordWrap = false;         
          break;
        case "image":
          oColumnDef.width = 100;
          oColumnDef.sortable = false;
          oColumnDef.visible = false;
          oColumnDef.editable = false;
          oColumnDef.wordWrap = false;        
          break;
        default:
          oColumnDef.width = 50;
          oColumnDef.sortable = true;
          oColumnDef.visible = true;
          oColumnDef.editable = false;
          oColumnDef.wordWrap = false;         
          break;                           
      }
      aColumns.push(oColumnDef);
    }
    return aColumns;                                                    //return the array
 }//getColumnDefArray
]]></mx:Script>
 
  <mx:XML id="xmlCatalog">
    <catalog>
      <product productId="1">
        <name>Nokia 6010</name>
        <description>Easy to use without sacrificing style, the Nokia 6010 phone offers functional voice communication supported by text messaging, multimedia messaging, mobile internet, games and more</description>
        <price>99.99</price>
        <image>assets/pic/Nokia_6010.gif</image>
        <series>6000</series>
        <triband>false</triband>
        <camera>false</camera>
        <video>false</video>
        <highlight1>MMS</highlight1>
      <highlight2>Large color display</highlight2>
      </product>
      <product productId="2">
        <name>Nokia 3100 Blue</name>
        <description>Light up the night with a glow-in-the-dark cover - when it's charged with light you can easily find your phone in the dark. When you get a call, the Nokia 3100 phone flashes in tune with your ringing tone. And when you snap on a Nokia Xpress-on™ gaming cover*, you'll get luminescent light effects in time to the gaming action.</description>
        <price>139</price>
        <image>assets/pic/Nokia_3100_blue.gif</image>
        <series>3000</series>
        <triband>true</triband>
        <camera>false</camera>
        <video>false</video>
        <highlight1>Glow-in-the-dark</highlight1>
      <highlight2>Flashing lights</highlight2>
      </product>
      <product productId="3">
        <name>Nokia 3100 Pink</name>
        <description>Light up the night with a glow-in-the-dark cover - when it's charged with light you can easily find your phone in the dark. When you get a call, the Nokia 3100 phone flashes in tune with your ringing tone. And when you snap on a Nokia Xpress-on™ gaming cover*, you'll get luminescent light effects in time to the gaming action.</description>
        <price>139</price>
        <image>assets/pic/Nokia_3100_pink.gif</image>
        <series>3000</series>
        <triband>true</triband>
        <camera>false</camera>
        <video>false</video>
        <highlight1>Glow-in-the-dark</highlight1>
      <highlight2>Flashing lights</highlight2>
      </product>
      <product productId="4">
        <name>Nokia 3120</name>
        <description>Designed for both business and pleasure, the elegant Nokia 3120 phone offers a pleasing mix of features. Enclosed within its chic, compact body, you will discover the benefits of tri-band compatibility, a color screen, MMS, XHTML browsing, cheerful screensavers, and much more.</description>
        <price>159.99</price>
        <image>assets/pic/Nokia_3120.gif</image>
        <series>3000</series>
        <triband>true</triband>
        <camera>false</camera>
        <video>false</video>
        <highlight1>Multimedia messaging</highlight1>
      <highlight2>Animated screensavers</highlight2>
      </product>
      <product productId="5">
        <name>Nokia 3220</name>
        <description>The Nokia 3220 phone is a fresh new cut on some familiar ideas - animate your MMS messages with cute characters, see the music with lights that flash in time with your ringing tone, download wallpapers and screensavers with matching color schemes for the interface.</description>
        <price>159.99</price>
        <image>assets/pic/Nokia_3220.gif</image>
        <series>3000</series>
        <triband>false</triband>
        <camera>true</camera>
        <video>false</video>
        <highlight1>MIDI tones</highlight1>
      <highlight2>Cut-out covers</highlight2>
      </product>
    </catalog>
  </mx:XML>
</mx:Application>