We help IT Professionals succeed at work.

Treeviewitem and for loop

285 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
Comment
Watch Question

Guy Hengel [angelIII / a3]Billing Engineer
CERTIFIED EXPERT
Most Valuable Expert 2014
Top Expert 2009

Commented:
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

Author

Commented:
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.
Billing Engineer
CERTIFIED EXPERT
Most Valuable Expert 2014
Top Expert 2009
Commented:
This one is on us!
(Get your first solution completely free - no credit card required)
UNLOCK SOLUTION

Author

Commented:
Thank you for the explanation. It was spot on.

Gain unlimited access to on-demand training courses with an Experts Exchange subscription.

Get Access
Why Experts Exchange?

Experts Exchange always has the answer, or at the least points me in the correct direction! It is like having another employee that is extremely experienced.

Jim Murphy
Programmer at Smart IT Solutions

When asked, what has been your best career decision?

Deciding to stick with EE.

Mohamed Asif
Technical Department Head

Being involved with EE helped me to grow personally and professionally.

Carl Webster
CTP, Sr Infrastructure Consultant
Empower Your Career
Did You Know?

We've partnered with two important charities to provide clean water and computer science education to those who need it most. READ MORE

Ask ANY Question

Connect with Certified Experts to gain insight and support on specific technology challenges including:

  • Troubleshooting
  • Research
  • Professional Opinions
Unlock the solution to this question.
Join our community and discover your potential

Experts Exchange is the only place where you can interact directly with leading experts in the technology field. Become a member today and access the collective knowledge of thousands of technology experts.

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

OR

Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.