frameworks/projects/spark/asdoc/en_US/spark/components/gridClasses/examples/GridColumnVisibilityExample.mxml

<?xml version="1.0" encoding="utf-8"?>
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<!--

Demonstrate the GridColumn visible property and the support for dynamically adding and removing columns.

After selecting a column it's visibility can be changed, a copy of the column can be inserted, and the column can be removed.

The DataGrid columns property is a mutable list - an IList, like ArrayList - and columns can be added or removed at any time.  The difference 
between an IList and an intrinsic collection type like Array or Vector is that ILists dispatch events when they're changed.   That's why the
DropDownList, whose dataProvider is the list of columns, tracks the changes made with the Add/Remove buttons.

Changing a column's visibility does not change its presence or position in the columns IList but it prevents the DataGrid from displaying it.

-->

<s:Application 
    xmlns:fx="http://ns.adobe.com/mxml/2009" 
    xmlns:s="library://ns.adobe.com/flex/spark">
    
    <fx:Script>
        <![CDATA[
            // Insert a column to the left of specified column
            private function addNewColumn(column:GridColumn):void
            {
                const newColumn:GridColumn = new GridColumn();
                newColumn.dataField = column.dataField;
                newColumn.headerText = column.headerText + "+";
                dataGrid.columns.addItemAt(newColumn, column.columnIndex);
            }
            
            // Remove the specified column
            private function removeColumn(column:GridColumn):void
            {
                dataGrid.columns.removeItemAt(column.columnIndex);
            }
        ]]>
    </fx:Script>
    
    <s:Panel title="Spark DataGrid Control Example which demonstrates the GridColumn visible property and dynamically adding and removing columns"
             width="75%" height="75%" 
             horizontalCenter="0" verticalCenter="0">
        
        <s:controlBarContent>
            <s:HGroup verticalAlign="baseline">
                <s:DropDownList id="ddl" prompt="Select" dataProvider="{dataGrid.columns}" labelField="headerText"/>
                <s:Label text="Visible:"/>
                <s:CheckBox selected="@{ddl.selectedItem.visible}" enabled="{ddl.selectedItem}"/>
                <s:Button label="Add" click="addNewColumn(ddl.selectedItem)" enabled="{ddl.selectedItem}"/>
                <s:Button label="Remove" click="removeColumn(ddl.selectedItem)" enabled="{ddl.selectedItem}"/>
            </s:HGroup>
        </s:controlBarContent>
        
        <s:DataGrid id="dataGrid" left="5" right="5" top="5" bottom="5">
            <s:columns>
                <s:ArrayList>
                    <s:GridColumn dataField="key" headerText="Key"/>
                    <s:GridColumn dataField="name" headerText="Name"/>
                    <s:GridColumn dataField="price" headerText="Price"/>
                    <s:GridColumn dataField="call" headerText="Call"/>
                </s:ArrayList>
            </s:columns>
            
            <s:ArrayCollection>
                <s:DataItem key="1000" name="Abrasive" price="100.11" call="false"/>
                <s:DataItem key="1001" name="Brush" price="110.01" call="true"/>
                <s:DataItem key="1002" name="Clamp" price="120.02" call="false"/>
                <s:DataItem key="1003" name="Drill" price="130.03" call="true"/>
                <s:DataItem key="1004" name="Epoxy" price="140.04" call="false"/>
                <s:DataItem key="1005" name="File" price="150.05" call="true"/>
                <s:DataItem key="1006" name="Gouge" price="160.06" call="false"/>
                <s:DataItem key="1007" name="Hook" price="170.07" call="true"/>
                <s:DataItem key="1008" name="Ink" price="180.08" call="false"/>
                <s:DataItem key="1009" name="Jack" price="190.09" call="true"/>             
            </s:ArrayCollection>
        </s:DataGrid>    
    </s:Panel>    
</s:Application>