C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

public partial class Default3 : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["Data"].ConnectionString);
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            loadUsersData();
        }
    }
    protected void loadUsersData()
    {
        con.Open();
        SqlCommand cmd = new SqlCommand("Select * from UsersData", con);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        da.Fill(ds);
        int count = ds.Tables[0].Rows.Count;
        con.Close();
        if (ds.Tables[0].Rows.Count > 0)
        {
            gridView.DataSource = ds;
            gridView.DataBind();
        }
        else
        {
            ds.Tables[0].Rows.Add(ds.Tables[0].NewRow());
            gridView.DataSource = ds;
            gridView.DataBind();
            int columncount = gridView.Rows[0].Cells.Count;
            lblmsg.Text = " No data found !!!";
        }
    }
    protected void gridView_RowEditing(object sender, GridViewEditEventArgs e)
    {
        gridView.EditIndex = e.NewEditIndex;
        loadUsersData();
    }
    protected void gridView_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        string id = gridView.DataKeys[e.RowIndex].Values["id"].ToString();
        TextBox UserName = (TextBox)gridView.Rows[e.RowIndex].FindControl("txtUserName");
        TextBox Password = (TextBox)gridView.Rows[e.RowIndex].FindControl("txtPassword");
        con.Open();
        SqlCommand cmd = new SqlCommand("update UsersData set UserName='" + UserName.Text + "', Password='" + Password.Text + "' where id=" + id, con);
        cmd.ExecuteNonQuery();
        con.Close();
        lblmsg.BackColor = Color.Blue;
        lblmsg.ForeColor = Color.White;
        lblmsg.Text = id + "        Updated successfully........    ";
        gridView.EditIndex = -1;
        loadUsersData();
    }
    protected void gridView_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    {
        gridView.EditIndex = -1;
        loadUsersData();
    }
    protected void gridView_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        string id = gridView.DataKeys[e.RowIndex].Values["id"].ToString();
        con.Open();
        SqlCommand cmd = new SqlCommand("delete from UsersData where id=" + id, con);
        int result = cmd.ExecuteNonQuery();
        con.Close();
        if (result == 1)
        {
            loadUsersData();
            lblmsg.BackColor = Color.Red;
            lblmsg.ForeColor = Color.White;
            lblmsg.Text = id + "      Deleted successfully.......    ";
        }
    }
    protected void gridView_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            string id = Convert.ToString(DataBinder.Eval(e.Row.DataItem, "id"));
            Button lnkbtnresult = (Button)e.Row.FindControl("ButtonDelete");
            if (lnkbtnresult != null)
            {
                lnkbtnresult.Attributes.Add("onclick", "javascript:return deleteConfirm('" + id + "')");
            }
        }
    }
    protected void gridView_RowCommand(object sender, GridViewCommandEventArgs e)
    {
        if (e.CommandName.Equals("AddNew"))
        {
            TextBox inid = (TextBox)gridView.FooterRow.FindControl("inid");
            TextBox inUserName = (TextBox)gridView.FooterRow.FindControl("inUserName");
            TextBox inPassword = (TextBox)gridView.FooterRow.FindControl("inPassword");
            con.Open();
            SqlCommand cmd =
                new SqlCommand(
                    "insert into UsersData(id,UserName,Password) values('" + inid.Text + "','" +
                    inUserName.Text + "','" + inPassword.Text + "')", con);
            int result = cmd.ExecuteNonQuery();
            con.Close();
            if (result == 1)
            {
                loadUsersData();
                lblmsg.BackColor = Color.Green;
                lblmsg.ForeColor = Color.White;
                lblmsg.Text = inid.Text + "      Added successfully......    ";
            }
            else
            {
                lblmsg.BackColor = Color.Red;
                lblmsg.ForeColor = Color.White;
                lblmsg.Text = inid.Text + " Error while adding row.....";
            }
        }
    }

    protected void gridView_SelectedIndexChanged(object sender, EventArgs e)
    {

    }
}

public void readplc()
            {
                Opc.URL url = new Opc.URL("opcda://localhost/Matrikon.OPC.Simulation.1");
                Opc.Da.Server server = null;
                OpcCom.Factory fact = new OpcCom.Factory();
                server = new Opc.Da.Server(fact, null);
                try
                {
    
                    server.Connect(url, new Opc.ConnectData(new System.Net.NetworkCredential()));
                }
                catch (Exception ecy)
                {
    
                }
                // Create a group
                Opc.Da.Subscription group;
                Opc.Da.SubscriptionState groupState = new Opc.Da.SubscriptionState();
                groupState.Name = "Group";
                groupState.Active = true;
                group = (Opc.Da.Subscription)server.CreateSubscription(groupState);
                // add items to the group.
                Opc.Da.Item[] items = new Opc.Da.Item[2];
                items[0] = new Opc.Da.Item();
                items[0].ItemName = "Random.Int1";
                items[1] = new Opc.Da.Item();
                items[1].ItemName = "Random.Time";
                items = group.AddItems(items);

                    group.DataChanged += new Opc.Da.DataChangedEventHandler(OnTransactionCompleted);

            }
    
            public void OnTransactionCompleted(object group, object hReq, Opc.Da.ItemValueResult[] items)
            {

                for (int i = 0; i < items.GetLength(0); i++)
                {
                 
                    try
                    {
    
                        string a = items[i].Value.ToString();
                        string b = items[i].ItemName;
                        string c = items[i].Key;

                        MySqlConnection conn = new MySqlConnection("server=localhost;user id=localhost;password=localhost;database=localhost;pooling=false"); 
                        conn.Open();
                        conn.Close();
                    }
                    catch (Exception ec)
                    {
                    }
                    
                }
    
            }

private void dataGridView1_CellLeave(object sender, DataGridViewCellEventArgs e)
        {
            string x = (string)dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value;

            MessageBox.Show(x);

        }