Solved

TreeView - get all selected (checkbox) nodes on button click

Posted on 2008-06-17
7
9,661 Views
Last Modified: 2013-11-05
I have a treeview control with checkboxes that I need to get the unique identifier value of all checked nodes on a button click.  I dont need the control to update until the user actually clicks the button.  A stored procedure generates a datatable with the following structure.

SportID        SportName      LeagueID        League
------------------------------------------------------------------
101               Basketball        400              1st Grade
101               Basketball        401              2nd Grade
102               Volleyball         650               Girls Red Div
etc.

The Treeview is build the tree using the code below.  

The Treeview displays SportName and League, but the value that I need to retrieve is the LeagueID.  Once the user clicks the button, I need a list of all the checked LeagueIDs.  In a datagrid I would do something like
For n as integer = 0 to Datagrid.Rows.Count -1
       If Datagrid.Rows(n).Cells(5).Value = true then
               LeagueID = Datagrid.Rows(n).Cells("LeagueID").value
               stringbuilder or something with LeagueID
       end if
Next.  

But I can't seem to find a similar method to work with the treeview.

Thanks,
Clint...

     
0
Comment
Question by:clintnash
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 3
7 Comments
 
LVL 24

Expert Comment

by:Jeff Certain
ID: 21806252
Basically the same idea. Iterate through the list of nodes and get the keys for all selected nodes. The routine below uses recursion to add all checked nodes to a list; you could create a list for keys only quite easily.
(use)	Dim list As New List(Of TreeNode)
	GetSelectedNodes(treeView.Nodes, list)
 
Private Sub GetSelectedNodes(ByVal nodes As TreeNodeCollection, ByRef list As List(Of TreeNode))
	For Each node As TreeNode In nodes
		If node.Checked Then list.Add(node)
		GetSelectedNodes(node.Nodes, list)
	Next
End Sub

Open in new window

0
 
LVL 1

Author Comment

by:clintnash
ID: 21807988
Well I am able to pull the text value from the node, but what I need is the uniqueID for the node.  I am not sure why I can't see the code that inserted to show how I am building the tree, so if you are seeing this twice sorry.  I pass a datatable to the following sub.

    Private Sub BuildTree(ByVal DT As DataTable)
        TreeView1.Nodes.Clear()
        Dim root As New TreeNode("Sport")
        Dim sportNodes() As TreeNode
        Dim sportNode As TreeNode
        For Each Dr As DataRow In DT.Rows
            sportNodes = root.Nodes.Find(Dr("SportID"), True)
            If sportNodes IsNot Nothing And sportNodes.Length > 0 Then
                sportNode = sportNodes(0)
            Else
                sportNode = root.Nodes.Add(Dr("SportID"), Dr("Sportname"))
            End If
            sportNode.Nodes.Add(Dr("LeagueID"), Dr("League"))
        Next
        TreeView1.Nodes.Add(root)
    End Sub

Using the code above I am able to sucessfully fill the list with "League", what I need is "LeagueID".  Hopefully that is an easy change, but I have spent the afternoon trying to work it out without success.

thanks,
Clint...
0
 
LVL 24

Accepted Solution

by:
Jeff Certain earned 500 total points
ID: 21808070
I'd change your code just a little bit to use the Tag property, since it seems that the key isn't recoverable (for some inexplicable reason).


  Private Sub BuildTree(ByVal DT As DataTable)
        TreeView1.Nodes.Clear()
        Dim root As New TreeNode("Sport")
        Dim sportNodes() As TreeNode
        Dim sportNode As TreeNode
        For Each Dr As DataRow In DT.Rows
            sportNodes = root.Nodes.Find(Dr("SportID"), True)
            If sportNodes IsNot Nothing And sportNodes.Length > 0 Then
                sportNode = sportNodes(0)
            Else
                sportNode = root.Nodes.Add(Dr("SportID"), Dr("Sportname"))
            End If
            sportNode.Nodes.Add(Dr("LeagueID"), Dr("League")).Tag(Dr("LeagueID").ToString)
        Next
        TreeView1.Nodes.Add(root)
    End Sub
 
(use)		Dim list As New List(Of String)
		GetSelectedNodes(treeView.Nodes, list)
 
	Private Sub GetSelectedNodes(ByVal nodes As TreeNodeCollection, ByRef list As List(Of String))
		For Each node As TreeNode In nodes
			If node.Checked Then list.Add(node.Tag)
			GetSelectedNodes(node.Nodes, list)
		Next
	End Sub

Open in new window

0
PeopleSoft Has Never Been Easier

PeopleSoft Adoption Made Smooth & Simple!

On-The-Job Training Is made Intuitive & Easy With WalkMe's On-Screen Guidance Tool.  Claim Your Free WalkMe Account Now

 
LVL 1

Author Comment

by:clintnash
ID: 21818377
Fantastic, made it quite a step further today, I do still have one final issue. The code as it is above didn't work when I cut it in, I made the following change to it and all seems okay now.

sportNode.Nodes.Add(Dr("LeagueID"), Dr("League")) .Tag=(Dr("LeagueID").ToString)

The problem that I cant seem to get past is, it works just fine as long as I only select the child nodes (League / LeagueID), if I select its parent (Sport / SportID), it errors with a Object Reference not set to an instance of an object.

I do, very much, appreciate your help!


0
 
LVL 24

Expert Comment

by:Jeff Certain
ID: 21818778
hmmm... where is it erroring out? on the line where we add the tag to the list?
0
 
LVL 1

Author Comment

by:clintnash
ID: 21823088
Actually, its was a bit of the forest for the trees problem, the error was being generated when I was looping through the list and using stringbuilder to construct a comma seperated string of the selected items. When I saw your post on where it was erroring out, it clicked.  I put in a "isnot nothing" check on list.item(n) as I loop through and its working perfectly now.

thanks again for all your help...
0
 
LVL 24

Expert Comment

by:Jeff Certain
ID: 21823226
Great! Glad we got it working.
0

Featured Post

Salesforce Has Never Been Easier

Improve and reinforce salesforce training & adoption using WalkMe's digital adoption platform. Start saving on costly employee training by creating fast intuitive Walk-Thrus for Salesforce. Claim your Free Account Now

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Calculating holidays and working days is a function that is often needed yet it is not one found within the Framework. This article presents one approach to building a working-day calculator for use in .NET.
If you need to start windows update installation remotely or as a scheduled task you will find this very helpful.
Come and listen to Percona CEO Peter Zaitsev discuss what’s new in Percona open source software, including Percona Server for MySQL (https://www.percona.com/software/mysql-database/percona-server) and MongoDB (https://www.percona.com/software/mongo-…
Michael from AdRem Software outlines event notifications and Automatic Corrective Actions in network monitoring. Automatic Corrective Actions are scripts, which can automatically run upon discovery of a certain undesirable condition in your network.…

717 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question