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DradDrop between with in a node

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Akhil Dwivedi
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Akhil Dwivedi asked on 30 Oct 2009, 09:46 AM
Hi

     i an usin treeview. How can i stop dragdrop between nodes but requies drag drop within a node item.

like
NodeA
        A
        B
        C
        D
NodeB
        E
        F
        G
        H
The item should be dragging within items of NodeA not within Item of NodeA and NodeB

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Bobi
Telerik team
answered on 03 Nov 2009, 01:43 PM
Hello Akhil Dwivedi,

If I understand you correctly you want to use Drag/Drop only between items that are in the same TreeViewItem node and to disable Drag/Drop between items which are in different nodes.

If so please take a look at the following :

1.Define some RadTreeView and attach to PreviewDragEnded event.

<telerik:RadTreeView IsDragDropEnabled="True" PreviewDragEnded="RadTreeView_PreviewDragEnded" >
                <telerik:RadTreeViewItem Header="A" IsExpanded="True" x:Name="NodeA">
                    <telerik:RadTreeViewItem Header="E" IsExpanded="True"/>
                    <telerik:RadTreeViewItem Header="C" />
                    <telerik:RadTreeViewItem Header="D" />
                </telerik:RadTreeViewItem>
                <telerik:RadTreeViewItem Header="B" IsExpanded="True">
                    <telerik:RadTreeViewItem Header="F"/>
                    <telerik:RadTreeViewItem Header="G" />
                    <telerik:RadTreeViewItem Header="H" />
                </telerik:RadTreeViewItem>
   </telerik:RadTreeView>

2.Add the following in code behind:

private void RadTreeView_PreviewDragEnded(object sender, Telerik.Windows.Controls.RadTreeViewDragEndedEventArgs e)
        {
            var treeViewItemDestination = e.TargetDropItem;
            if (treeViewItemDestination == null || treeViewItemDestination.ParentItem != this.NodeA)
            {
                e.Handled = true;
            }
        }

That is all you have to do in order to accomplish the desired functionality.
So if you follow the above steps then you will be able to Drag/Drop only between the items in node A.
And if you try to Drag/Drop items from node A to node B then nothing happens.
I hope that this will help you.

Regards,
Boryana
the Telerik team

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Akhil Dwivedi
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answered on 04 Nov 2009, 09:27 AM
Thanks for ur reply
          It is fine for node A only but these parent nodes and child items are dynamic so how for others?
0
Bobi
Telerik team
answered on 06 Nov 2009, 12:29 PM
Hello Akhil Dwivedi,

The important here is to subscribe to :
private void RadTreeView_PreviewDragEnded(object sender, Telerik.Windows.Controls.RadTreeViewDragEndedEventArgs e)
        {
            var treeViewItemDestination = e.TargetDropItem;
            if (treeViewItemDestination == null || treeViewItemDestination.ParentItem != this.NodeA)
            {
                e.Handled = true;
            }
        }

Here you can define your own logic , I mean a particular condition showing whether user can drop item or not.  Alternatively you can use the Item level for a condition or something similar.
You can also take a look at our online example:
http://demos.telerik.com/silverlight/#TreeView/DragDrop

I hope that this will be helpful.


Kind regards,
Boryana
the Telerik team

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Watch a video on how to optimize your support resource searches and check out more tips on the blogs.
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Bobi
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Akhil Dwivedi
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