' See if the targetNode is currently selected, ' if so no need to validate again If Not (selectedTreeview.SelectedNode Is targetNode) Then ' Select the node currently under the cursor ' As the mouse moves over nodes, provide feedback to ' the user by highlighting the node that is the ' current drop target Dim pt As Point = _ĬType(sender, TreeView).PointToClient( New Point(e.X, e.Y))ĭim targetNode As TreeNode = selectedTreeView.GetNodeAt(pt) True) = False Then Exit Sub ' Get the TreeView raising the event (incase multiple on form) Dim selectedTreeview As TreeView = CType(sender, TreeView) ' Check that there is a TreeNode being dragged If e.Data.GetDataPresent( " ", _
Treeview visual basic.net code#
Therefore, we have to validate the TreeNode as the cursor passes over it by handling the DragOver event:Ĭopy Code Public Sub TreeView1_DragOver( ByVal sender As System. However, it is also important to ensure that a particular TreeNode within the TreeView is a valid target for the drag drop operation. Validating the Drop TargetĪbove, we looked at ensuring only TreeNodes can be dragged over the TreeView. However, on a form, there may be many other controls calling the DoDragDrop method by setting the AllowDrop property to True on a control, you are specifying that it will react whenever any object is dragged over it. In this example, we only have one control that is initiating a drag drop operation. It is important to check that the object of the type you are expecting is present in the drag drop data (in this case, a TreeNode). Note, you may only select the effect(s) that were specified when the drag drop operation was initiated with the DoDragDrop method (see Initiating the Drag above). If a TreeNode is found, then we specify that the Move effect will be displayed on the cursor, otherwise we specify that the None effect will be displayed. True) Then ' TreeNode found allow move effectĪll we are doing here is checking if there is an object present in the drag drop operation that we are happy to be dropped onto the TreeView, in this case a TreeNode.
' See if there is a TreeNode being dragged If e.Data.GetDataPresent( " ", _ Copy Code Public Sub TreeView1_DragEnter( ByVal sender As System.
0 kommentar(er)
