Treeview Node expand

[naveen veda]

hi,

i have build a tree based on load on demand method (ie, while expanding the root node only the child nodes are getting populated).

now my problem is,

i want to search the employee node in the treeview.

at first, only one node is there in a treeview. i need to call the node_Expand event every time based on the hierarchy of the employee.

the tree view is adding nodes for the first level.next time it gives nullreference exception.
Ex,
---
AAAA
--BBB
-------B1
-------B2
--CCC
--DDD
-------D1
-------D2
------------D21
--EEE

in the above tree i am going to find D21. first it builds the first level ie, AAA,BBB,CCC,DDD,EEE  without error. the next level D1,D2 also bulit without error.next D2 node expanding time it gives the error.

how can i solve this. how to find the employee.

thanks,
mano.

[Veselin Vasilev]

Hello naveen veda,

What is the error?

Can you paste here the relevant code? How exactly do you built the second level?

Sincerely yours,
Veselin Vasilev
the Telerik team

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[naveen veda]

Hi,

Within the button click event
~~~~~~~~~~~~~~~~~~~~~~

  
              for (int i = 1; i < strLine.Length - 1; i++)
                {
               Session["treenodeExpand"] = strLine[i].ToString();
               Session["EmpID"] = Laser.App.BLL.bllManager.fn_GetEmpIfromNode(Convert.ToInt32(strLine[i]));
               ManagerTreeView_NodeExpand(sender, new RadTreeNodeEventArgs());

              }

TreeNode Expand Event
~~~~~~~~~~~~~~~~~~~~

protected void ManagerTreeView_NodeExpand(object o, RadTreeNodeEventArgs e)
    {

        try
        {
            Label lblSaveMessage = (Label)(Master.FindControl("SaveMessagelbl"));
            lblSaveMessage.Text = string.Empty;

           

                DataTable dtChildNode = new DataTable();
                dtChildNode = Laser.App.BLL.bllManager.fn_GetChildNodes(Convert.ToInt32(Session["treenodeExpand"].ToString()));

                int iChildCount = 0;
                iChildCount = dtChildNode.Rows.Count;
                foreach (DataRow row in dtChildNode.Rows)
                {
                    RadTreeNode node = new RadTreeNode();
                    node.Text = row["employeename"].ToString();
                    node.Value = row["employeeid"].ToString();

                
                    if (iChildCount > 0)
                    {
                        node.ExpandMode = ExpandMode.ClientSide;
                    }
                  ManagerTreeView.Nodes.FindNodeByValue(Convert.ToString(Session["EmpID"])).Nodes.Add(node);
                
                }
                ManagerTreeView.Nodes.FindNodeByValue(Convert.ToString(Session["EmpID"])).Expanded = true;
                ManagerTreeView.Nodes.FindNodeByValue(Convert.ToString(Session["EmpID"])).ExpandMode = ExpandMode.ClientSide;
             }
Catch(Exception ex)
{
}
}


Error
~~~~
that bold letter line gives me the error  as " Object reference not set with an object"

at first level it adds the node to treeview.
second level it gives me the error.

[Yana]

Hello Naveen,

You cannot add child nodes to a different from the expanded node in OnNodeExpand event handler. 

Kind regards,
Yana
the Telerik team

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