Treeview drag doesn't display no. of item selected

[SANJAY]

Hi All,

I have treeview with drag and drop enabled and also set the "multiSelect" property to true to select multiple node while drag. I need to show no. of selected nodes to drag like in windows file system while doing drag and drop operation.

Thanks,

[Svett]

Hello Sanjay,

You can use the PreviewDragHint event of RadTreeViewDragDropService to create a custom drag hint image in the following way:

C#

this.radTreeView1.TreeViewElement.DragDropService.PreviewDragHint += this.OnPreviewDragHint;

private void OnPreviewDragHint(object sender, Telerik.WinControls.PreviewDragHintEventArgs e)
{
    int count = this.radTreeView1.SelectedNodes.Count;

    if (count > 1)
    {
        Size size = new Size(50, 50);
        Bitmap bitmap = new Bitmap(size.Width, size.Height);
        using (Graphics g = Graphics.FromImage(bitmap))
        {
            string countText = "Count: " + count;
            SizeF textSize = g.MeasureString(countText, this.Font);
            float x = (size.Width - textSize.Width) / 2;
            float y = (size.Height - textSize.Height) / 2;
            g.DrawString(countText, this.Font, Brushes.Black, x, y);
        }

        e.UseDefaultHint = false;
        e.DragHint = bitmap;
    }
}

VB.NET

AddHandler radTreeView1.TreeViewElement.DragDropService.PreviewDragHint, AddressOf OnPreviewDragHint

Private Sub OnPreviewDragHint(sender As Object, e As Telerik.WinControls.PreviewDragHintEventArgs)
    Dim count As Integer = Me.radTreeView1.SelectedNodes.Count

    If count > 1 Then
        Dim size As New Size(50, 50)
        Dim bitmap As New Bitmap(size.Width, size.Height)
        Using g As Graphics = Graphics.FromImage(bitmap)
            Dim countText As String = "Count: " + count
            Dim textSize As SizeF = g.MeasureString(countText, Me.Font)
            Dim x As Single = (size.Width - textSize.Width) / 2
            Dim y As Single = (size.Height - textSize.Height) / 2
            g.DrawString(countText, Me.Font, Brushes.Black, x, y)
        End Using

        e.UseDefaultHint = False
        e.DragHint = bitmap
    End If
End Sub

I hope this helps.

Greetings,
Svett
the Telerik team