Hello everyone,

I've reached a dead end right now trying to get my TreeNodes to load dynamically.

I start by adding a base node as a starting point.

        Dim trnBase As New TreeNode


        trnBase.Text = "Search"


        tvw_Search.Nodes.Add(trnBase)

At this point there are no problems. trnBase has been added to tvw_Search. And the indexOf property of trnBase has been set to 0 (which will be used later in this subroutine).

Later on in this same subroutine I itterate through a DataTable containing my Nodes. Each itteration I check the ParentNodeIndex value. I then use that to get the ParentNode from the node collection of tvw_Search. Then I add the record as a node to the ParentNode.

        Dim intParentNodeIndex As Integer = drRow(4)





        Dim trnChildNode As New TreeNode


        trnChildNode.Text = drRow(7)





        Dim trnParentNode As New TreeNode


        trnParentNode = tvw_Search.Nodes.Item(intParentNodeIndex)


        trnParentNode.Nodes.Add(trnChildNode)

Now this is where I have trouble. The problem lies in the IndexOf property of the child nodes. When I added trnBase (the first set of code) trnBase gets assigned "IndexOf = 0". However, the nodes that are added via the Database (the second set of code) are not assigned an IndexOf value.

In other words, in my DataTable the first 5 records have "ParentIndexOf = 0". They are added to trnBase (indexOf = 0) no problem because trnBase was assigned an Index value of 0. The problem begins when I try to add nodes to these 5 new nodes. These 5 new nodes were never assigned an IndexOf value. Not only that, they aren't recognized in the tvw_Search nodes collection. When I do a "For each node in" tvw_Search, it only loops once for Node "trnBase", even though the first 5 records were added to "trnBase".

The only difference that could make any difference in my code is the last line in each set:

tvw_Search.Nodes.Add()





trnBase.Nodes.Add()

Is there something different I have to do as far as adding nodes to nodes to that of nodes to Trees?

Thank you for any help.

Alec

Hello!

I have the same problem, did you ever find a solution?

This is my code:

TreeView tree = new TreeView();

   TreeNode userTools = new TreeNode();
   userTools.Text="User Tools";
   tree.Nodes.Add(userTools);
   
   TreeNode userTool1 = new TreeNode();
   userTool1.Text="User Tool 1";
   tree.Nodes[tree.Nodes.IndexOf(userTools)].Nodes.Add(userTool1);

   TreeNode userTool2 = new TreeNode();
   userTool2.Text="User Tool 2";
   tree.Nodes[tree.Nodes.IndexOf(userTool1)].Nodes.Add(userTool2);

this.Controls.Add(tree);


I am able to add userTool1 to userTools, but when I want to add userTool2 to userTool1, I can't, because userTool1 has an index of -1(not assigned).

Hi,

You need to look for the node in the level you add it.

Your example would be:

TreeView tree = new TreeView();

   TreeNode userTools = new TreeNode();
   userTools.Text="User Tools";
   tree.Nodes.Add(userTools);
   
   TreeNode userTool1 = new TreeNode();
   userTool1.Text="User Tool 1"; 
   tree.Nodes[tree.Nodes.IndexOf(userTools)].Nodes.Add(userTool1);
   // tree.Nodes[0].Nodes.Add(userTool1); // This also works

   TreeNode userTool2 = new TreeNode();
   userTool2.Text="User Tool 2";
   tree.Nodes[tree.Nodes.IndexOf(userTools)].Nodes[userTools.Nodes.IndexOf(userTool1)].Nodes.Add(userTool2);
   // tree.Nodes[0].Nodes[0].Nodes.Add(userTool2); // This also works

this.Controls.Add(tree);

Remember the structure and hierarchy of the tree, in this case userTools belongs to the tree, but userTool1 belongs to userTools and userTool2 to userTool1
I hope it helps

Regards,
Diego Merayo

Hi,

I'm populating my treeview from SQL database. My table design is as follows:

MenuId     |  MenuName      |  MenuUrl     |  MenuType  | MenuParent
1                  Alert                     ----              root               0
2                  Safety                   ----              document       1
3                  Precaution             ----             folder              2
4                  Caution                 ----             folder              3

Each menu is linked to its parentid through Menuparent column. My problem is how to make the coding very dynamic. The treelevel could go upto 6-7 levels. The coding I have written is:

TVMenu.ImageUrl = "../Images/folder.gif"
TVMenu.SelectedImageUrl = "../Images/folderopen.gif"
TVMenu.Visible = True
da = New SqlDataAdapter("select * from menutrees where MenuType='root'", conn)
da.Fill(dsRoot, "menutrees")
For Each rowRoot In dsRoot.Tables("menutrees").Rows
   nodeRoot = New TreeNode
   nodeRoot.Text = rowRoot("MenuName")
   nodeRoot.Type = rowRoot("MenuType")
   nodeRoot.NavigateUrl = rowRoot("MenuUrl")
   nodeRoot.ImageUrl = "../Images/root.gif"
   nodeRoot.SelectedImageUrl = "../Images/root.gif"
   strid = rowRoot("MenuId")
   TVMenu.Nodes.Add(nodeRoot)
   da = New SqlDataAdapter("select * from menutrees where menuparent=" & strid & " ", conn)
   da.Fill(dsChild1, "menutrees")
   For Each rowChild1 In dsChild1.Tables("menutrees").Rows
      nodeChild1 = New TreeNode
      nodeChild1.Text = rowChild1("MenuName")
      nodeChild1.Type = rowChild1("MenuType")
      'nodeChild1.NavigateUrl = rowChild1("MenuUrl")
      If nodeChild1.Type = "document" Then
         nodeChild1.ImageUrl = "../Images/doc.gif"
         nodeChild1.SelectedImageUrl = "../Images/doc.gif"
      End If
      strid = rowChild1("MenuId")
      nodeRoot.Nodes.Add(nodeChild1)
      da = New SqlDataAdapter("select * from menutrees where menuparent=" & strid & " ", conn)
      da.Fill(dsChild2, "menutrees")
      For Each rowChild2 In dsChild2.Tables("menutrees").Rows
         ----
         ----
         ----

So u guyz must have got an idea what I'm trying to do. I tried writing it as a procedure which will call itself. The problem is if any child record is present then datareader updates the dataset thereby old looping is lost and new loop begins. I hope you understood my problem. If anyone can give me some ideas how to go about I would appreciate.

@ recursivity thingy 

If you have a SQL Server (2005 +) there is a really nice clause to help you with recursivity problem, it is the WITH clause, see example D of: http://msdn.microsoft.com/en-us/library/ms175972.aspx

 As for the other problem, dunno.

Personaly I am trying to add child nodes when client clicks on parent node, but even though it is adding the node, it ain't showing up on the client. (I use a debug label to count the number of childnodes added to the parent node and it shows the increase)

 Hope it helps in regards to recursivity

 

Edit: Note that I do not want to add everything right of the bat ti minimize the response time and the load on the sql server

Edit2: sorry for the necro, forgot to look up the date before posting