code not executed

[curiousvbnet]

Hi,

I try to make an event dragdrop work in a treeview called Treeview1, but i can see that when i select an item in the treeview, to copy it at another place ,the code below is not executed at all.
Only the Treeview1_ItemDrag is considered.
Could you explain me what happens?

Thanks a lot for your help.
Regards

Nathalie

Here is the code i use

[blue] Private Sub TreeView1_ItemDrag(ByVal sender As Object, ByVal e As System.Windows.Forms.ItemDragEventArgs) Handles TreeView1.ItemDrag[/blue]
        DoDragDrop(e.Item, DragDropEffects.Copy)
    End Sub
    'on teste que les données d'arrivée sont bien des treenode(Treeview1 est ici le contrôle d'arrivée); si c'est le cas la copie du noeud est exéctée

   [blue] Private Sub TreeView1_DragEnter(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles TreeView1.DragEnter[/blue]
        If e.Data.GetDataPresent("System.Windows.Forms.TreeNode", True) Then
            e.Effect = DragDropEffects.Copy
        Else
            e.Effect = DragDropEffects.None
        End If
    End Sub

    'cet évènement survient quand la souris se balade sur le contrôle d'arrivée; il vérifie si le drop reçoit bien un noeud
    'pt :e.X et e.Y sont les coordonées écran : on ls transforme en coordonnées du contrôle client, cad du treeview1(contrôle d'arrivée)
[blue]
    Private Sub TreeView1_DragOver(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles TreeView1.DragOver[/blue]
        Dim pt As Point, NodeCible As TreeNode, NodeSource As TreeNode
        If e.Data.GetDataPresent("system.Windows.Forms.TreeNode", False) Then
            Exit Sub
        Else
            pt = CType(sender, TreeView).PointToClient(New Point(e.X, e.Y))
            NodeCible = Me.TreeView1.GetNodeAt(pt)
            NodeSource = CType(e.Data.GetData("System.Windows.Forms.TreeNode"), TreeNode)

            If Not (Me.TreeView1.SelectedNode Is NodeCible) Then
                Me.TreeView1.SelectedNode = NodeCible
            End If 'fin de If Not (Me.TreeView1.SelectedNode Is NodeCible)


            Do Until NodeCible Is Nothing
                If NodeCible Is NodeSource Then
                    e.Effect = DragDropEffects.None
                    Exit Sub
                End If 'fin de  If NodeCible Is NodeSource Then
                NodeCible = NodeCible.Parent
            Loop
            e.Effect = DragDropEffects.Copy

        End If 'fin de  If e.Data.GetDataPresent("system.Windows.Forms.TreeNode", False)

    End Sub

    'dans cette procédure on utilise la méthode GetData pour extraire les données que l'on fait glisser.


   [blue] Private Sub TreeView1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles TreeView1.DragDrop[/blue]
        Dim nodesource As TreeNode
        Dim nodecible As TreeNode
        Dim verifparent As TreeNode

        If e.Data.GetDataPresent("system.Windows.Forms.TreeNode", False) Then
            Exit Sub
        Else
            nodesource = CType(e.Data.GetData("system.Windows.Forms.TreeNode"), TreeNode)
            nodecible = TreeView1.SelectedNode
            verifparent = nodecible


            Do Until verifparent Is Nothing
                If verifparent Is nodesource Then
                    Exit Sub
                    verifparent = verifparent.Parent
                End If
            Loop
            nodesource.Remove()
            'si il n'y a pas de noeud cible alors on ajooute le noeud source au treeview, en fait on considère que le noeud cible est le noeud source.
            'si le neoud cible existe , on lui ajoute le noeud spource que l'on a copié
            'le noeud copié (noeud source) devient le noeud sélectionné
            If nodecible Is Nothing Then
                TreeView1.Nodes.Add(nodesource)
            Else
                nodecible.Nodes.Add(nodesource)
            End If
            nodesource.EnsureVisible()
            TreeView1.SelectedNode = nodesource

        End If

    End Sub

 

[cjelec]

I think that there is a property called AllowDragDrop?
If you enable this on the TreeView, it should work.

 

[curiousvbnet]

Hi,

Thanks a lot , it works better but it does not give any result; in fact the program stops just after the drag_over event but i will see with the debbuger where there is a pb .

Moreover , does this event(dragdrop), takes in consideration that in the database, now there will be a new relation parent/child because of a node copy in the treeview1).
Because at the beginning, the treeview is built with the help of this table , using the relation parent/child to buit the treeview.

Thanks again

Regards.

Nathalie

 

[cjelec]

I have just spotted in your line:

If e.Data.GetDataPresent("system.Windows.Forms.TreeNode", False) Then
   Exit Sub

Should it be:

If Not e.Data.GetDataPresent("system.Windows.Forms.TreeNode", False) Then
   Exit Sub