树视图无限循环

Question

I'm trying make one treeView with infinite subgroups.

I can add my groups but I couldn't add my subgroups. For subgroup the output shows my group value. My code for subgroup is below: I think there is something wrong with my SQL string but I don't know what is.

private void chilnoddoldur(DataTable dt, TreeNodeCollection treeNodeCollection)
//fill childnodes
{
    foreach (DataRow dr in dt.Rows)
    {
        TreeNode child = new TreeNode();
        child.Text = dr["kgr_ad"].ToString();
        child.Value = dr["kgr_bsno"].ToString();
        if (child.ChildNodes.Count > 0)
        {
            child.PopulateOnDemand = true;
        }
        child.SelectAction = TreeNodeSelectAction.SelectExpand;
        child.Expand();
        child.Selected = true;
        treeNodeCollection.Add(child);
   }
}

Here is the SQL Code:

SqlConnection conn = b.baglan();
if (conn.State == ConnectionState.Open) 
{ 
    conn.Close();
} 
conn.Open(); 
SqlCommand cmd = new SqlCommand("select kgr_sno,kgr_ad,kgr_bsno from kulgrp where kgr_bsno=@id", conn); 
cmd.Parameters.AddWithValue("@id", kgrSno); 
SqlDataAdapter da = new SqlDataAdapter(cmd); 
DataTable dt = new DataTable(); 
da.Fill(dt); 
kgrBsno.ChildNodes.Clear(); 
chilnoddoldur(dt, kgrBsno.ChildNodes); 
conn.Close();

Answer 1

If some node has child nodes, you should create recursion - call chilnoddoldur method again, but it's important to pass appropriate argments: datatable should have only rows with child elements, and treeNodeCollection should represent childNodeCollection of the current node. It should look something like this:

if (child.ChildNodes.Count > 0)
{
    child.PopulateOnDemand = true;
    //recursion call - childDt is datatable with childnode rows
    chilnoddoldur(childDt, child.ChildNodes)
}

If some of this childnodes has its own childnodes, it will make another recursion call, if not, when method runs out, it will continue running its parent method, etc.

I hope I was clear enough to give you a basic idea.

Answer 2

foreach (DataRow dr in dt.Rows)
    {
        TreeNode child = new TreeNode();
        child.Text = dr["kgr_ad"].ToString();
        child.Value = dr["kgr_sno"].ToString();

           child.CollapseAll();

            kgrBsno.ChildNodes.Add(child);
            AltGruplariYaz(child, Convert.ToInt32(dr["kgr_sno"]));
}

the answer of my question