ListControl Drag&Drop with Descritpions

[Matias]

Hi,

I'm using the ListBox control with the Scheduler one, so when the user drags an item with description from the ListBox and drops it into the scheduler a new appointment is created. I saw the Demo you provide, however, this one uses plain RadListDataItem and RadListVisualItem. On the description of each item there's a phone number. I have created a new "Add Appointment" form to hold the phone number. My Question is: how can I Drag&Drop ListBox Items with descriptions and retrieve not only the Item text but the description too?

I've tried the following code, but "item" is always null.

Private Sub radListBox1_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs)
    If e.Button <> MouseButtons.Left Then
        Return
    End If

    If Me.isDragging Then
        Return
    End If

    Dim currentPosition As Point = e.Location

    If (Math.Abs(currentPosition.X - Me.mouseDownPosition.X) >= SystemInformation.DragSize.Width) OrElse (Math.Abs(currentPosition.Y - Me.mouseDownPosition.Y) >= SystemInformation.DragSize.Height) Then
        Me.isDragging = True
        Dim dragObject As New DragObject()
        Dim item As DescriptionTextListVisualItem = TryCast(Me.LBox1.ElementTree.GetElementAtPoint(e.Location), DescriptionTextListVisualItem)

        If item IsNot Nothing Then
            dragObject.Values.Add(AppointmentFields.Summary, item.Text)
            dragObject.Values.Add(AppointmentFields.Description, item.DescriptionText)

            dragObject.Status = AppointmentFields.Summary

            TryCast(sender, RadListControl).DoDragDrop(dragObject, DragDropEffects.Copy)
        End If
    End If
End Sub

Thank you very much for your time and attention,
Matias.

[Peter]

Hello Matias,

Thank you for writing.

The DescriptionTextListVisualItem is a composite element and it contains a few LigthVisualElements. When you call GetElementAtPoint method the result is a LigthVisualElement which is nested in the DescriptionTextListVisualItem. The parent of this LightVisualElement is the DescriptionTextListVisualItem and you can get it with the following lines of code:

Dim radElement As RadElement = Me.RadListControl1.ElementTree.GetElementAtPoint(e.Location)
If radElement Is Nothing Then Exit Sub

Dim item As DescriptionTextListVisualItem = radElement.FindAncestor(Of DescriptionTextListVisualItem)()

If item IsNot Nothing Then

I hope this helps.

Kind regards,
Peter
the Telerik team

[Matias]

Thanks peter for your quick answer.
The code you provided was pretty helpful and I managed to return the Item Description, however, now I cannot return the Item text

This is the code as I'm using it now.

Dim radElement As RadElement = LBox1.ElementTree.GetElementAtPoint(e.Location)
If radElement Is Nothing Then Exit Sub

Dim item As DescriptionTextListVisualItem = radElement.FindAncestor(Of DescriptionTextListVisualItem)()

If item IsNot Nothing Then
    dragObject.Values.Add(AppointmentFields.Summary, item.Text) 'item.Text returns an empty string.
    dragObject.Values.Add(AppointmentFields.Description, item.DescriptionText)

    dragObject.Status = AppointmentFields.Summary

    TryCast(sender, RadListControl).DoDragDrop(dragObject, DragDropEffects.Copy)
End If

Am I doing something wrong?
Thank you again!

[Matias]

Solved the Item.text issue. The correct way to retrieve that information is Item.Data.text.
Thanks again for the time spent.

[Peter]

Hello Matias,

I am happy that you resolved the issue the with the text and I can confirm that this approach is correct.

Greetings,
Peter
the Telerik team