Treeview Nodes.Clear

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

Hi,

I am trying to clear my treeview when I add new items (to refresh) and It
only seems to be removing the first Parent Node, none of the children below
are being cleared.

Am I doing something wrong? The below code is based on retreiving data from
a hierarchical table:
Thanks,Dianna

Private Sub PopulateTreeView()

treeEvents.Nodes.Clear()

Dim cmd As String

cmd = "Select * From dbo.fncGetEventTree(null) ORDER BY lineage +
Ltrim(Str(node,6,0))"

Dim da As New System.Data.SqlClient.SqlDataAdapter(cmd,
ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString)

da.Fill(ds)

treeEvents.Nodes.Add(New TreeNode("Event Groups"))

Dim tNode As New TreeNode

tNode = treeEvents.Nodes(0)

PopulateTreeView(0, tNode)

tNode.Expand()
End Sub

Private Sub PopulateTreeView(ByVal inParentID As Integer, ByRef
inTreeNode As TreeNode)

Dim newtag As String

dv = New DataView(ds.Tables(0))

dv.RowFilter = "parent_id = " & inParentID

Dim drv As DataRowView

For Each drv In dv

Dim parentnode As TreeNode

parentnode = New TreeNode(drv.Item("event"))

inTreeNode.Nodes.Add(parentnode)

parentnode.Tag = newtag

'call the routine again to find childern of this record.
PopulateTreeView(drv.Item("event_id"), parentnode)

Next drv

End Sub
 
Dianna said:
Hi,

I am trying to clear my treeview when I add new items (to refresh) and It
only seems to be removing the first Parent Node, none of the children
below
are being cleared.

Am I doing something wrong? The below code is based on retreiving data
from
a hierarchical table:
Thanks,Dianna

Private Sub PopulateTreeView()

treeEvents.Nodes.Clear()

Dim cmd As String

cmd = "Select * From dbo.fncGetEventTree(null) ORDER BY lineage +
Ltrim(Str(node,6,0))"

Dim da As New System.Data.SqlClient.SqlDataAdapter(cmd,
ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString)

da.Fill(ds)

treeEvents.Nodes.Add(New TreeNode("Event Groups"))

Dim tNode As New TreeNode

tNode = treeEvents.Nodes(0)

PopulateTreeView(0, tNode)

tNode.Expand()
End Sub

Private Sub PopulateTreeView(ByVal inParentID As Integer, ByRef
inTreeNode As TreeNode)

Dim newtag As String

dv = New DataView(ds.Tables(0))

dv.RowFilter = "parent_id = " & inParentID

Dim drv As DataRowView

For Each drv In dv

Dim parentnode As TreeNode

parentnode = New TreeNode(drv.Item("event"))

inTreeNode.Nodes.Add(parentnode)

parentnode.Tag = newtag

'call the routine again to find childern of this record.
PopulateTreeView(drv.Item("event_id"), parentnode)

Next drv

End Sub
Click to expand...
I've tried to replicate your problem in test Windows VB apps in both Visual
Studio .NET 2003 and in Visual Studio 2005. The Clear() method clears all
nodes.
As I may have made invalid assumptions about the software you are using, its
edition and version, and I guessed at the project type and template, please
supply that information.
I may be belaboring the obvious here, but have you stepped through your
subprocedure in the debugger to see the state of the Treeview object just
after the Clear() executes?
 
What I am noticing is that when I do
Treeview.Nodes.clear it removes the top parent to the tree ("Event Groups")
Everything else under the parent (treeEvents.Nodes(0).Nodes) - the children
stays there. Even treeview.Nodes.count says 0. However,
treeEvents.Nodes(0).Nodes.count says 17..?

It looks like I can clear the children by doing
treeEvents.Nodes(0).Nodes.Clear, but this is being built dynamically using a
hierarchical table. The user can have as many children as he wants. So the
trick will be to find out how many levels in the tree.

I think, I'm guessing.
 
Hi Peter,

Oh Well, this was kind of dumb, but it was not the treeview. It was my
dataset. Everytime I called the routine it appened to it.

Thanks.

Dianna
 
Dianna said:
Hi Peter,

Oh Well, this was kind of dumb, but it was not the treeview. It was my
dataset. Everytime I called the routine it appened to it.

Thanks.

Dianna
Click to expand...
All's well that ends well :)
 
Back
Top