Recursive TreeView in ASP.NET

Question

I have an object of type list from which I wish to use to populate a treeview in asp.net c#.

Each object item has:

id | Name | ParentId

Answer 1

I think this should get you started. I created a MyObject class to mimic your object .

public class MyObject
{
    public int Id;
    public int ParentId;
    public string Name;
}

Here is a method to recursivley add tree view nodes based on the list.

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        List list = new List();
        list.Add(new MyObject(){Id=1, Name="Alice", ParentId=0});
        list.Add(new MyObject(){Id=2, Name="Bob", ParentId=1});
        list.Add(new MyObject(){Id=3, Name="Charlie", ParentId=1});
        list.Add(new MyObject(){Id=4, Name="David", ParentId=2});            

        BindTree(list, null);            
    }
}

private void BindTree(IEnumerable list, TreeNode parentNode)
{
    var nodes = list.Where(x => parentNode == null ? x.ParentId == 0 : x.ParentId == int.Parse(parentNode.Value));
    foreach (var node in nodes)
    {
        TreeNode newNode = new TreeNode(node.Name, node.Id.ToString());
        if (parentNode == null)
        {
            treeView1.Nodes.Add(newNode);
        }
        else
        {
            parentNode.ChildNodes.Add(newNode);
        }
        BindTree(list, newNode);
    }
}