Solved

Treeviewitem and for loop

Posted on 2014-11-05
4
119 Views
Last Modified: 2014-11-07
I have a legacy code I'm maintaining that uses a for loop to bind data rows from a dataset into a tree view for wpf. A request came in to add a root node to the existing 2 level tree view. I'm not familiar on how to assign child nodes in treeview control and a few attempts so far has been unsuccessful.  

For Each iRow In iDataSet.Tables("Table1").Rows
                If iRow("TABNAME") <> PreviousTab Then
                    Dim oTreeNodeTabName As New TreeViewItem
                    oTreeNodeTabName.Header = iRow("TABNAME")
                    oTreeNodeTabName.Tag = Nothing
                                        
                    _TreeView.Items.Add(oTreeNodeTabName)
                End If

                If iRow("TYPEDESC") <> PreviousDesc Then
                    Dim oTreeNodeHeader As New TreeViewItem
                    oTreeNodeHeader.Header = iRow("TYPEDESC")
                    oTreeNodeHeader.Tag = Nothing
                    count += 1                    
                    _TreeView.items.Add(oTreeNodeHeader)
                End If

                Dim oTreeNode As New TreeViewItem
                oTreeNode.Header = iRow("EVENTDATE") & "   " & iRow("TYPEDESC")
                oTreeNode.Tag = iRow("VIEWPARMS")
                                
                Dim tvItem As TreeViewItem = _TreeView.Items(count)
                tvItem.Items.Add(oTreeNode)

Open in new window


The data in the table should look like below:

TABNAME     TYPEDESC     EVENTDATE     VIEWPARMS
A                     ABC                MM/DD/YYYY  1234567
A                     ABC                MM/DD/YYYY  2164546
A                     DEF                MM/DD/YYYY  1546546
B                     GHI                MM/DD/YYYY  6548484

I want to use for loop to add a root node for TABNAME so the treeview will have 3 tiers instead of 2:

TABNAME
       |_       TYPEDESC
                          |_    EVENTDATE TYPEDESC
0
Comment
Question by:lo_oscar
  • 2
  • 2
4 Comments
 
LVL 142

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 40425727
it should look like this, assuming the data comes in ordered by tabname and typedes:

string PreviousTab = string.Empty
string PreviousType = string.Empty

Dim oTreeNodeTab As TreeViewItem
Dim oTreeNodeType As TreeViewItem
Dim oTreeNodeChild As TreeViewItem

For Each iRow In iDataSet.Tables("Table1").Rows
       If iRow("TABNAME") <> PreviousTab Then
                oTreeNodeTab = new  TreeViewItem()
                    oTreeNodeTab .Header = iRow("TABNAME")
                    oTreeNodeTab .Tag = Nothing
                                       
                    _TreeView.Items.Add(oTreeNodeTab )
                   PreviousTab=  iRow("TABNAME")
                End If

                If iRow("TYPEDESC") <> PreviousDesc Then
                    oTreeNodeType  = New TreeViewItem
                    oTreeNodeType .Header = iRow("TYPEDESC")
                    oTreeNodeType .Tag = Nothing
                    _oTreeNodeTab .items.Add(oTreeNodeType )
                   PreviousDesc =  iRow("TYPEDESC")
                End If

                oTreeNodeChild =  New TreeViewItem
                oTreeNodeChild .Header = iRow("EVENTDATE") & "   " & iRow("TYPEDESC")
                oTreeNodeChild .Tag = iRow("VIEWPARMS")
                                
                oTreeNodeType .Items.Add(oTreeNodeChild )
end for                                  

Open in new window

0
 

Author Comment

by:lo_oscar
ID: 40426780
Thanks. I have try this too but are getting an error

"Element already has a logical parent. It must be detached from the old parent before it is attached to the new one."

This happens when the second oTreeNodeChild is added while I run debug.
0
 
LVL 142

Accepted Solution

by:
Guy Hengel [angelIII / a3] earned 500 total points
ID: 40427810
I am quite sure you did not use the code as meant.

in your code you had this:
Dim oTreeNodeChild As New TreeViewItem

but it must be (before the loop):
Dim oTreeNodeChild As TreeViewItem
and inside the loop:
oTreeNodeChild =  New TreeViewItem

the issue is that if you don't create a new object, it will
0
 

Author Comment

by:lo_oscar
ID: 40428494
Thank you for the explanation. It was spot on.
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

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

Wouldn’t it be nice if you could test whether an element is contained in an array by using a Contains method just like the one available on List objects? Wouldn’t it be good if you could write code like this? (CODE) In .NET 3.5, this is possible…
The ECB site provides FX rates for major currencies since its inception in 1999 in the form of an XML feed. The files have the following format (reducted for brevity) (CODE) There are three files available HERE (http://www.ecb.europa.eu/stats/exch…
Windows 10 is mostly good. However the one thing that annoys me is how many clicks you have to do to dial a VPN connection. You have to go to settings from the start menu, (2 clicks), Network and Internet (1 click), Click VPN (another click) then fi…
Internet Business Fax to Email Made Easy - With  eFax Corporate (http://www.enterprise.efax.com), you'll receive a dedicated online fax number, which is used the same way as a typical analog fax number. You'll receive secure faxes in your email, f…

895 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

Need Help in Real-Time?

Connect with top rated Experts

18 Experts available now in Live!

Get 1:1 Help Now