Library tutorials & articles
TreeView Control
Drag and Drop
This one look me a while to work out, but here it is.
Firstly, add a TreeView control to your project and name it tvProject. Next, add an Image List Control, set the image size to 16x16, add a 3 images, and set their keys to Root, FolderClosed and Item.
Then, set the TreeView's OLEDragMode to 1-ccOLEDragAutomatic, and its OLEDropMode to 1-ccOLEDropManual. Also, set its ImageList property to the ImageList control you have just added.
The following code will allow you to move nodes and its children around on the control (like in explorer when you drag folders to new locations etc).
'// variable that tells us if
'// we are dragging (ie the user is dragging a node from this treeview
control
'// or not (ie the user is trying to drag an object from another
'// control and/or program)
Private blnDragging As Boolean
Private Sub Form_Load()
'// fill the control with some dummy nodes
With tvProject.Nodes
.Add , , "Root",
"Root Item", "Root"
'// add some child folders
.Add "Root", tvwChild,
"ChildFolder1", "Child Folder 1", "FolderClosed"
.Add "Root", tvwChild,
"ChildFolder2", "Child Folder 2", "FolderClosed"
.Add "Root", tvwChild,
"ChildFolder3", "Child Folder 3", "FolderClosed"
'// add some children to the
folders
.Add "ChildFolder1",
tvwChild, "Child1OfFolder1", "Child 1 Of Folder 1",
"Item"
.Add "ChildFolder1",
tvwChild, "Child2OfFolder1", "Child 2 Of Folder 1",
"Item"
.Add "ChildFolder2",
tvwChild, "Child1OfFolder2", "Child 1 Of Folder 2",
"Item"
End With
End Sub
Private Sub tvProject_MouseDown(Button As Integer, Shift As Integer, x As Single, y As Single)
Dim nodNode As Node
'// get the node we are over
Set nodNode = tvProject.HitTest(x, y)
If nodNode Is Nothing Then Exit Sub '// no node
'// ensure node is actually selected, just incase we
start dragging.
nodNode.Selected = True
End Sub
'// occurs when the user starts dragging
'// this is where you assign the effect and the data.
Private Sub tvProject_OLEStartDrag(Data As MSComctlLib.DataObject,
AllowedEffects As Long)
'// Set the effect to move
AllowedEffects = vbDropEffectMove
'// Assign the selected item's key to the DataObject
Data.SetData tvProject.SelectedItem.Key
'// we are dragging from this control
blnDragging = True
End Sub
'// occurs when the object is dragged over the
control.
'// this is where you check to see if the mouse is over
'// a valid drop object
Private Sub tvProject_OLEDragOver(Data As MSComctlLib.DataObject, Effect As
Long, Button As Integer, Shift As Integer, x As Single, y As Single, State
As Integer)
Dim nodNode As Node
'// set the effect
Effect = vbDropEffectMove
'// get the node that the object is being dragged over
Set nodNode = tvProject.HitTest(x, y)
If nodNode Is Nothing Or blnDragging = False Then
'// the dragged object is not
over a node, invalid drop target
'// or the object is not from
this control.
Effect = vbDropEffectNone
End If
End Sub
'// occurs when the user drops the object
'// this is where you move the node and its children.
'// this will not occur if Effect = vbDropEffectNone
Private Sub tvProject_OLEDragDrop(Data As MSComctlLib.DataObject, Effect As
Long, Button As Integer, Shift As Integer, x As Single, y As Single)
Dim strSourceKey As String
Dim nodTarget As Node
'// get the carried data
strSourceKey = Data.GetData(vbCFText)
'// get the target node
Set nodTarget = tvProject.HitTest(x, y)
'// if the target node is not a folder or the root item
'// then get it's parent (that is a folder or the root
item)
If nodTarget.Image <> "FolderClosed" And
nodTarget.Key <> "Root" Then
Set nodTarget = nodTarget.Parent
End If
'// move the source node to the target node
Set tvProject.Nodes(strSourceKey).Parent = nodTarge
'// NOTE: You will also need to update the key to reflect
the changes
'// if you are using it
'// we are not dragging from this control any more
blnDragging = False
'// cancel effect so that VB doesn't muck up your
transfer
Effect = 0
End Sub
James first started this website when learning Visual Basic back in 1999 whilst studying his GCSEs. The site grew steadily over the years while being run as a hobby - to a regular monthly audience ...
Related articles
Related discussion
-
Run-time error '91'
by converter2009 (1 replies)
-
VB6 Runtime error 381 subsript out of range Error
by Uncle (2 replies)
-
passing and reading parameters from using Shell
by jigartoliya (0 replies)
-
Convert C++ code to VB6
by mawcot (4 replies)
-
listbox scrollbar
by Dennijr (10 replies)
Related podcasts
-
Christian Beauclair
14 mai 2008 (�mission #0074) ::.Christian Beauclair: Stratégies de migration VB6 vers .NET Nous discutons avec Christian Beauclair des stratégies de migration VB6 vers .NET. Entre autres, nous discutons comment utiliser le "VB 6 Code Advisor" et le "Interop Forms Toolkit" pour ajouter la puiss...
I tried your treeview example and when I try to add and image it is telling me that I need to initilaize the image first. Can you tell me what that means and how to fix it
I tried this and recieved the following: Compile error: variable not defined..."TreeView" is highlited...anyone have any ideas?
gabriel medina
gxsoft@hotmail.com
http://www.pldental.com
Hi,
Found this very good tutorial because its nearly exact the problem i have with my TreeView,...
...but unfortunatly, i can't get it to work...
Set the same settings like in the tutorial, but nothing happens.
I try to drag and drop, but it seems, there is no action by the script,...
Any suggetions, what my failure could be?
Thanx for help
LittleMik
Enjoyed the piece on drag and drop treeview.
I use VS6 under XP and in that environment the DataObject declaration is
Data As MSComctl2.DataObject
rather than the reference in the posting
Hyperlink to articles on DataSource and imagelist would be handy but they are both documented in MSDN if you throw the rigth incantation at it.
Nigel
Just what i needed for a contact list im doing for my MSN Clone. Excellent!
Can this be implemented using ASP pages as well?
Thanks.
I hope someOne found this useful
Private Sub Form_Load()
With TreeView1
.Style = tvwTreelinesPlusMinusPictureText
.LineStyle = tvwRootLines
.PathSeparator = "\"
.Indentation = Screen.TwipsPerPixelX * 5 '256
.LabelEdit = tvwManual
.SingleSel = False
.HideSelection = False
.ImageList = ImageList1
.Refresh
End With
Call ShowEstructure
End Sub
Private Sub ShowEstructure()
Dim i As Byte
Dim j As Byte
Dim k As Byte
Dim Max As Byte
Dim sp As String
Dim sh As String
Dim sh2 As String
Dim TotalSecciones As Byte
Dim TotalPosiciones As Byte
Dim rsSeccions As New ADODB.Recordset
Dim rsPositions As New ADODB.Recordset
TreeView1.Nodes.Clear
Set grsGral = New ADODB.Recordset
grsGral.Open "EXEC spSQL_ShowDepartments", gConnectionString, adOpenStatic, adLockReadOnly, 1
Max = grsGral.RecordCount
For i = 1 To Max
'Actual Node
sp = "nodo" & CStr(i)
TreeView1.Nodes.Add , , sp, grsGral.Fields(1).Value, 1
grsGral.MoveNext
Next
grsGral.MoveFirst
For i = 1 To Max
' leaf
sp = "nodo" & CStr(i)
Set rsSeccions = New ADODB.Recordset
rsSeccions.Open "EXEC spSQL_ShowSeccions_forThis '" & grsGral.Fields(0).Value & "'", gConnectionString, adOpenStatic, adLockReadOnly, 1
TotalSecciones = rsSeccions.RecordCount
For j = 1 To TotalSecciones
' relative son
sh = sp & "-" & CStr(j) 'j
TreeView1.Nodes.Add sp, tvwChild, sh, rsSeccions.Fields(0).Value, 2
'*-*-*-
Set rsPositions = New ADODB.Recordset
rsPositions.Open "EXEC spSQL_ShowPositions_forThis '" & rsSeccions.Fields(1).Value & "'", gConnectionString, adOpenStatic, adLockReadOnly, 1
TotalPosiciones = rsPositions.RecordCount
For k = 1 To TotalPosiciones
' La clave del nodo hijo, relativo al nodo sP
sh2 = sh & "-" & CStr(k) 'j
TreeView1.Nodes.Add sh, tvwChild, sh2, rsPositions.Fields(0).Value, 3
rsPositions.MoveNext
Next
Set rsPositions = Nothing
'*--*-*-
rsSeccions.MoveNext
Next
Set rsSeccions = Nothing
grsGral.MoveNext
Next
Set grsGral = Nothing
End Sub
Hoped to find some example using directories and files...
Sorry, I went back and read it more closely. I just had to play around with the ImageList control to make it work.
I might have missed it, but I would have liked to have seen how to use images without having to go to the imagelist tutorial. I know you mentioned imagelist, but perhaps a brief explanation of using the imagelist control with TreeView would have been in order. If I missed it, I apologize. Thank you for a very helpful tutorial.
This thread is for discussions of TreeView Control.