Library tutorials & articles
TreeView Control
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 ...
Adding Nodes
Adding an item, or Node to the TreeView control is simple, once you know how. Adding a node uses the following syntax:
TreeView1.Nodes.Add Relative, Relationship, Key, Text, Image,
SelectedImage
All of this parameters are optional. As the TreeView control is made up of items in a Tree, Visual Basic needs to know where the new item goes. You use Relative and Relationship to specify this. Relative specifies a relation (an existing node) to the new node you are creating. Relationship specifies how the new node is related to this existing node. Possible relationships are:
tvwChild '// new node is a child (one level down) of the specified node
tvwFirst '// new node is first, at the same level of the specified node
tvwLast '// new node is last, at the same level of the specified node
tvwNext '// new node is after (at the same level) the specified node
tvwPrevious '// new node is before (at the same level) the specified node
Key is a unique indentifier for this node (but easier to remember than an Index ID), which can be a string. Text is the text to be displayed for this node. Image is the image to be displayed next to the node, specified from the bound Image List (discussed later), such as a folder. SelectedImage is the image to be displayed when the node is selected, such as an open folder, specified from the bound Image list (discussed later). Add a TreeView control to your form and enter the code below.
Private Sub Form_Load()
'// add some items
TreeView1.Nodes.Add , , "root", "Root Item"
TreeView1.Nodes.Add "root", tvwChild,
"child1_root", "Child1 of Root"
TreeView1.Nodes.Add "root", tvwChild,
"child2_root", "Child2 of Root"
TreeView1.Nodes.Add "child1_root", tvwChild,
"child1_child1", "Child1 of Child1"
'// make sure Child1 of Child1 is visible
TreeView1.Nodes("child1_child1").EnsureVisible
End Sub
Run the project. You should see something like the image below:
Notice that the last line in the Form_Load procedure uses the EnsureVisible method. This forces the specified node to become visible, by expanding another item in needed.
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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?
Very Good, You have helped me.
gabriel medina
gxsoft@hotmail.com
Good Example isn't it?
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 spSQLShowSeccionsforThis '" & 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.
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