I currently have a query which returns a data table into C# which is structured as follows:
ID | ParentID | ParentOfParentID | Name
What I'm looking to do is create a function to link this returned System.Data.DataTable to the ASP.NET treeview so that I get the structure as described - but so far I'm having no luck.
Any help would be appreciated - any treeviews which are 'better' than the ASP one would also be helpful! (As I don't quite like the ASP one).
Thanks
I wrote a BLOG entry on how to do this:
I don't know why you have ParentOfParentID, that seems redundant and would make moving nodes to a different parent really tough.
In code below "Node" class represents your one row from database (code is not included to convert database row to Node class object).
TreeView will look like this
<asp:TreeView ID="TreeView1" runat="server"
onselectednodechanged="TreeView1_SelectedNodeChanged"
ontreenodecollapsed="TreeView1_TreeNodeCollapsed"
ontreenodeexpanded="TreeView1_TreeNodeExpanded">
<SelectedNodeStyle BackColor="#FFFFCC" />
</asp:TreeView>
and page behind code is below. Method "getTreeMenu()" returns collection of nodes to display
public class Node
{
public int Id;
public string text;
public bool IsParent;
public int parentId;
public string url;
public bool IsSelected;
public bool IsExpanded = false;
}
public partial class SiteMaster : System.Web.UI.MasterPage
{
List<Node> lstNodes = new List<Node>();
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
bindTree();
}
}
TreeNode searchResult;
public void SelectNodesRecursive(string searchValue, TreeView Tv)
{
foreach (TreeNode tn in Tv.Nodes)
{
if (tn.Value == searchValue)
{
searchResult = tn;
break;
}
if (tn.ChildNodes.Count > 0)
{
foreach (TreeNode cTn in tn.ChildNodes)
{
int a = SelectChildrenRecursive(cTn, searchValue);
if (a == 1)
{
searchResult = cTn;
}
}
}
}
}
private int SelectChildrenRecursive(TreeNode tn, string searchValue)
{
if (tn.Value == searchValue)
{
searchResult = tn;
return 1;
}
if (tn.ChildNodes.Count > 0)
{
foreach (TreeNode tnC in tn.ChildNodes)
{
int a = SelectChildrenRecursive(tnC, searchValue);
if (a == 1)
{
searchResult = tnC;
return 1;
}
}
}
searchResult = null;
return 0;
}
private void bindTree()
{
TreeNode parent = null, child = null;
if (Session["TreeNodes"] == null)
{
lstNodes = getTreeMenu();
Session["TreeNodes"] = lstNodes;
}
else
{
lstNodes = (List<Node>)Session["TreeNodes"];
}
foreach (Node node in lstNodes)
{
if (node.IsParent && node.parentId == 0)
{
parent = new TreeNode { Text = node.text, Value = node.Id.ToString()};
TreeView1.Nodes.Add(parent);
parent.Selected = node.IsSelected;
parent.Expanded = node.IsExpanded;
}
else
{
if (node.IsParent)
{
SelectNodesRecursive(node.parentId.ToString(), TreeView1);
parent = searchResult;
child = new TreeNode { Text = node.text, Value = node.Id.ToString()};
parent.ChildNodes.Add(child);
child.Selected = node.IsSelected;
child.Expanded = node.IsExpanded;
}
else
{
child = new TreeNode { Text = node.text, Value = node.Id.ToString()};
SelectNodesRecursive(node.parentId.ToString(), TreeView1);
parent = searchResult;
if (parent != null)
{
parent.ChildNodes.Add(child);
child.Selected = node.IsSelected;
child.Expanded = node.IsExpanded;
}
else
{
child.Selected = node.IsSelected;
child.Expanded = node.IsExpanded;
}
}
}
}
}
private List<Node> getTreeMenu()
{
List<Node> treeSource = new List<Node>();
treeSource.Add(new Node { Id = 1, IsParent = true, parentId = 0, text = "parent1", url = "home.aspx?id=1", IsExpanded = true });
treeSource.Add(new Node { Id = 2, IsParent = false, parentId = 1, text = "Child 1", url = "page1.aspx" });
treeSource.Add(new Node { Id = 3, IsParent = false, parentId = 1, text = "Child 2", url = "Page2.aspx" });
treeSource.Add(new Node { Id = 4, IsParent = false, parentId = 1, text = "Child 3", url = "Page3.aspx" });
treeSource.Add(new Node { Id = 5, IsParent = true, parentId = 0, text = "parent 2", url = "home.aspx?id=5", IsExpanded = false });
treeSource.Add(new Node { Id = 6, IsParent = false, parentId = 5, text = "child 1", url = "page1.aspx" });
treeSource.Add(new Node { Id = 7, IsParent = true, parentId = 5, text = "parent 3", url = "home.aspx?id=7", IsExpanded=false });
treeSource.Add(new Node { Id = 14, IsParent = false, parentId = 7, text = "child 1", url = "page1.aspx" });
treeSource.Add(new Node { Id = 15, IsParent = false, parentId = 7, text = "child 2", url = "page2.aspx" });
treeSource.Add(new Node { Id = 8, IsParent = false, parentId = 5, text = "child 3", url = "Page3.aspx" });
treeSource.Add(new Node { Id = 9, IsParent = true, parentId = 0, text = "parent 4", url = "home.aspx?id=9", IsExpanded = false });
treeSource.Add(new Node { Id = 10, IsParent = false, parentId = 9, text = "child 1", url = "page1.aspx" });
treeSource.Add(new Node { Id = 11, IsParent = false, parentId = 9, text = "child 2", url = "Page2.aspx" });
treeSource.Add(new Node { Id = 12, IsParent = false, parentId = 9, text = "child 3", url = "Page3.aspx" });
treeSource.Add(new Node { Id = 13, IsParent = true, parentId = 0, text = "parent 5", url = "About.aspx" });
return treeSource;
}
protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
{
string selVal = TreeView1.SelectedValue;
lstNodes = (List<Node>)Session["TreeNodes"];
if (lstNodes != null)
{
Node nd = lstNodes.Find(n => n.Id.ToString() == selVal);
foreach (Node item in lstNodes.FindAll(n => n.Id.ToString() != selVal))
{
item.IsSelected = false;
}
nd.IsSelected = true;
Session["TreeNodes"] = lstNodes;
if (nd.url != "")
Response.Redirect(nd.url);
}
}
protected void TreeView1_TreeNodeExpanded(object sender, TreeNodeEventArgs e)
{
lstNodes = (List<Node>)Session["TreeNodes"];
if (lstNodes != null)
{
Node nd = lstNodes.Find(n => n.Id.ToString() == e.Node.Value);
nd.IsExpanded = true;
Session["TreeNodes"] = lstNodes;
}
}
protected void TreeView1_TreeNodeCollapsed(object sender, TreeNodeEventArgs e)
{
lstNodes = (List<Node>)Session["TreeNodes"];
if (lstNodes != null)
{
Node nd = lstNodes.Find(n => n.Id.ToString() == e.Node.Value);
nd.IsExpanded = false;
Session["TreeNodes"] = lstNodes;
}
}
}
Let me know if you have any questions
