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VB.Net How to completely clear a TreeView

Posted on 2010-09-10
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Last Modified: 2013-11-27
I need to completely clear a TreeView control ready to accept new nodes. I have tried a couple of solutions from the net but still end up with the new nodes being appended to the bottom of the existing.

tvwPreAlert.Nodes.Clear() just does not do the job.
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Question by:TeDeSm
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5 Comments
 
LVL 53

Accepted Solution

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Dhaest earned 500 total points
ID: 33645285
1. Have you programmatically looked at treeview.Nodes.Count to make sure there are now 0?

2. Did you call treeview.BeginUpdate() before calling treeview.Nodes.Clear()? If so, are you calling treeview.EndUpdate() afterwards?

3. How do you fill the treeview ? Is it through databinding ? If so, is your souce cleared ?
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LVL 18

Expert Comment

by:John (Yiannis) Toutountzoglou
ID: 33645327
try this ....
Private Sub TreeViewClear()
Dim x As Integer
With TreeView1.Nodes
For x = .Count To 1 Step -1
 .Remove x
Next x
End With
End Sub

Open in new window

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LVL 9

Expert Comment

by:richard_hughes
ID: 33645331
Hello TeDeSm

tvwPreAlert.Nodes.Clear() should work. How are you adding the items?

Also, are you re-adding the items after you clear them, perhaps in Page_Load outside of a if(!this.IsPostBack) check?

Thanks,

Richard Hughes
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LVL 17

Expert Comment

by:Zhaolai
ID: 33646319
Try

tvwPreAlert = New TreeView
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Author Closing Comment

by:TeDeSm
ID: 33646351
The treeview was being filled from a public arraylist. Clearing the array before re-filling handled the apparent append issue, BeginUpdate and EndUpdate dealt with the treeview nodes.
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