Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/11/29/dragging-and-dropping-items-in-a-flex-tree-control/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:XML id="xmlDP">
        <root>
            <para label="Paragraph 1" isBranch="true">
                <node label="Lorem ipsum dolor sit amet, consectetuer adipiscing elit." />
                <node label="Cras porttitor nunc a pede." />
                <node label="Nulla ac magna non risus accumsan egestas." />
                <node label="Aenean pretium porta felis." />
                <node label="Sed massa." />
            </para>
            <para label="Paragraph 2" isBranch="true">
                <node label="Pellentesque pretium eros id odio tincidunt lobortis." />
                <node label="Praesent vitae dolor eget nisl adipiscing pretium." />
                <node label="Fusce nonummy dignissim risus." />
                <node label="Nunc sodales, lectus vitae nonummy cursus, augue lectus auctor orci, vel aliquet enim neque vel eros." />
                <node label="Donec laoreet euismod libero." />
                <node label="Etiam ut lectus." />
            </para>
            <para label="Paragraph 3" isBranch="true">
                <node label="Maecenas ut nibh eu diam viverra suscipit." />
                <node label="Pellentesque auctor, turpis vel lobortis suscipit, neque tortor tristique nibh, venenatis suscipit nisl nisl eget magna." />
                <node label="Donec interdum." />
                <node label="Praesent diam." />
            </para>
            <para label="Paragraph 4" isBranch="true">
                <node label="Proin nulla." />
                <node label="Morbi tincidunt, sapien in sollicitudin venenatis, nibh tortor pretium ante, non pharetra urna dolor et libero." />
                <node label="In malesuada risus at neque." />
            </para>
            <para label="Paragraph 5" isBranch="true" />
        </root>
    </mx:XML>

    <mx:Tree id="tree"
            dataProvider="{xmlDP}"
            labelField="@label"
            showRoot="false"
            verticalScrollPolicy="on"
            alternatingItemColors="[#FFFFFF,#EEEEEE]"
            showScrollTips="true"
            dragEnabled="true"
            dropEnabled="true"
            dragMoveEnabled="true"
            width="300"
            rowCount="6" />

</mx:Application>

View source is enabled in the following example.

 

Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/09/19/dragging-rows-between-two-different-flex-datagrid-controls/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="horizontal"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Array id="arr">
        <mx:Object colA="Item A.0" colB="Item B.0" colC="Item C.0" />
        <mx:Object colA="Item A.1" colB="Item B.1" colC="Item C.1" />
        <mx:Object colA="Item A.2" colB="Item B.2" colC="Item C.2" />
        <mx:Object colA="Item A.3" colB="Item B.3" colC="Item C.3" />
        <mx:Object colA="Item A.4" colB="Item B.4" colC="Item C.4" />
        <mx:Object colA="Item A.5" colB="Item B.5" colC="Item C.5" />
        <mx:Object colA="Item A.6" colB="Item B.6" colC="Item C.6" />
        <mx:Object colA="Item A.7" colB="Item B.7" colC="Item C.7" />
        <mx:Object colA="Item A.8" colB="Item B.8" colC="Item C.8" />
        <mx:Object colA="Item A.9" colB="Item B.9" colC="Item C.9" />
    </mx:Array>

    <mx:ApplicationControlBar dock="true">
        <mx:Form>
            <mx:FormItem label="DataGrid #1:"
                    direction="horizontal">
                <mx:CheckBox id="dg1_dragEnabled"
                        label="dragEnabled" />
                <mx:CheckBox id="dg1_dropEnabled"
                        label="dropEnabled" />
                <mx:CheckBox id="dg1_dragMoveEnabled"
                        label="dragMoveEnabled" />
            </mx:FormItem>
            <mx:FormItem label="DataGrid #2:"
                    direction="horizontal">
                <mx:CheckBox id="dg2_dragEnabled"
                        label="dragEnabled" />
                <mx:CheckBox id="dg2_dropEnabled"
                        label="dropEnabled" />
                <mx:CheckBox id="dg2_dragMoveEnabled"
                        label="dragMoveEnabled" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:VBox width="50%">
        <mx:Label text="DataGrid #1" />
        <mx:DataGrid id="dataGrid1"
                width="100%"
                rowHeight="22"
                dataProvider="{arr}"
                dragEnabled="{dg1_dragEnabled.selected}"
                dragMoveEnabled="{dg1_dragMoveEnabled.selected}"
                dropEnabled="{dg1_dropEnabled.selected}"
                verticalScrollPolicy="on">
            <mx:columns>
                <mx:DataGridColumn dataField="colA"
                        headerText="Column A" />
                <mx:DataGridColumn dataField="colB"
                        headerText="Column B" />
                <mx:DataGridColumn dataField="colC"
                        headerText="Column C" />
            </mx:columns>
        </mx:DataGrid>
        <mx:Label text="{dataGrid1.dataProvider.length} items" />
    </mx:VBox>

    <mx:VBox width="50%">
        <mx:Label text="DataGrid #2" />
        <mx:DataGrid id="dataGrid2"
                width="100%"
                rowHeight="22"
                dataProvider="[]"
                dragEnabled="{dg2_dragEnabled.selected}"
                dragMoveEnabled="{dg2_dragMoveEnabled.selected}"
                dropEnabled="{dg2_dropEnabled.selected}"
                verticalScrollPolicy="on">
            <mx:columns>
                <mx:DataGridColumn dataField="colA"
                        headerText="Column A" />
                <mx:DataGridColumn dataField="colB"
                        headerText="Column B" />
                <mx:DataGridColumn dataField="colC"
                        headerText="Column C" />
            </mx:columns>
        </mx:DataGrid>
        <mx:Label text="{dataGrid2.dataProvider.length} items" />
    </mx:VBox>

</mx:Application>

View source is enabled in the following example.