TreeView with BackGroundWorker

Question

Hi Experts,

I am trying to Populate the treeview with the backgroundworker control but did not get the parent and child nodes in

expected hierarchy.. 

My coding:

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Configuration;

using System.Data.SqlClient;

namespace TvBackGroundWorker

{

    public partial class Form1 : Form

    {

        SqlConnection conn;

         TreeNode parentNode = null; 

         TreeNode childNode; 

        DataTable dt = new DataTable();

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            String connectionString;

            connectionString = ConfigurationManager.ConnectionStrings["ConnString"].ConnectionString;

            conn = new SqlConnection(connectionString);

            String Sequel = "SELECT MAINMNU,MENUPARVAL,STATUS FROM MNUPARENT ORDER BY 2";

            SqlDataAdapter da = new SqlDataAdapter(Sequel, conn); 

            conn.Open();

            da.Fill(dt);

            backgroundWorker1.RunWorkerAsync();

        }

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)

        {

            foreach (DataRow dr in dt.Rows)

            {

                parentNode = (TreeNode)treeView1.Invoke(new Add(Add1), new object[] { dr["MAINMNU"].ToString()});

                PopulateTreeView(Convert.ToInt32(dr["MENUPARVAL"].ToString()), parentNode); 

            } 

        }

        private void PopulateTreeView(int parentId, TreeNode parentNode)

        {

            String Seqchildc = "SELECT MENUPARVAL,FRM_CODE,FRM_NAME,MNUSUBMENU FROM MNUSUBMENU WHERE MENUPARVAL=" + parentId + "";

            SqlDataAdapter dachildmnuc = new SqlDataAdapter(Seqchildc, conn);

            DataTable dtchildc = new DataTable();

            dachildmnuc.Fill(dtchildc);

            foreach (DataRow dr in dtchildc.Rows)

            {

                if (parentNode == null)

                {  //childNode = treeView1.Nodes.Add(dr["FRM_NAME"].ToString()); 

                    childNode = (TreeNode)treeView1.Invoke(new Add(Add2), new object[] { dr["FRM_NAME"].ToString() });

                    

                }

                else

                {

                    //childNode = parentNode.Nodes.Add(dr["FRM_NAME"].ToString());

                    childNode = (TreeNode)treeView1.Invoke(new Add(Add2), new object[] { dr["FRM_NAME"].ToString() });

                    System.Threading.Thread.Sleep(1000);

                }

                PopulateTreeView(Convert.ToInt32(dr["MNUSUBMENU"].ToString()), childNode);

            }

 

        }

        public delegate TreeNode Add(string txt);

        public TreeNode Add1(string txt)

        {

            parentNode = treeView1.Nodes.Add(txt);

            return parentNode;

        }

        public TreeNode Add2(string txt)

        {

            if(parentNode == null)

                childNode = treeView1.Nodes.Add(txt);

            else

                childNode = parentNode.Nodes.Add(txt);

            return childNode;

            

        }

    }

}

Tables Used

For Root or Parent Nodes

CREATE TABLE [dbo].[MNUPARENT](

[MAINMNU] [varchar](20) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,

[STATUS] [varchar](1) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,

[MENUPARVAL] [int] IDENTITY(1,1) NOT NULL,

 CONSTRAINT [PK_MNUPARENT] PRIMARY KEY CLUSTERED 

(

[MENUPARVAL] ASC

)WITH (PAD_INDEX  = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]

) ON [PRIMARY]

Child Nodes

CREATE TABLE [dbo].[MNUSUBMENU](

[MENUPARVAL] [int] NOT NULL,

[FRM_CODE] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,

[FRM_NAME] [varchar](20) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,

[MNUSUBMENU] [int] NOT NULL,

[STATUS] [varchar](1) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,

PRIMARY KEY CLUSTERED 

(

[MNUSUBMENU] ASC

)WITH (PAD_INDEX  = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]

) ON [PRIMARY]

Sample Insert in MNUPARENT Table

INSERT INTO MNUPARENT(MAINMNU, STATUS, MENUPARVAL) VALUES('Finanace','Y',1)

INSERT INTO MNUPARENT(MAINMNU, STATUS, MENUPARVAL) VALUES('Inventory','Y',2)

Sample Insert in MNUSUBMENU Table

INSERT INTO MNUSUBMENU(MENUPARVAL,FRM_NAME,MNUSUBMENU,STATUS) VALUES(1,'Child Finance',10,'Y')

INSERT INTO MNUSUBMENU(MENUPARVAL,FRM_NAME,MNUSUBMENU,STATUS) VALUES(1,'Accounting',20,'Y')

INSERT INTO MNUSUBMENU(MENUPARVAL,FRM_NAME,MNUSUBMENU,STATUS) VALUES(20,'Audit',30,'Y')

INSERT INTO MNUSUBMENU(MENUPARVAL,FRM_NAME,MNUSUBMENU,STATUS) VALUES(30,'Acc. Standards',40,'Y')

Any help appreciated.

Thanks Shankar