Insert a data in sql server with vb.net C#

//Bussiness Class Layer//

using System;  
using System.Collections.Generic;
using System.Linq; using System.Text;
using System.Data;
using System.Data.SqlClient;
namespace BussinessLayer
    {
public class BLLCounter
            {
string ConnectionStr = “Data Source=SINGH-LAPTOP;Initial Catalog=Bank;Persist Security Info=True;User ID=sa;Password=microsoft;Pooling=False;”;

public int CreateCounter(string CounterId, string CounterName)
      {
SqlConnection con = new SqlConnection(ConnectionStr);
string sql = “insert into tblCounter(CounterId,CounterName) values(@CounterId,@COunterName)”;
SqlCommand cmd = new SqlCommand(sql, con);
cmd.Parameters.AddWithValue(“@CounterId”, CounterId);
cmd.Parameters.AddWithValue(“@CounterName”, CounterName);
try
      {
con.Open();
return cmd.ExecuteNonQuery();//insert update delete
      }
catch (Exception)
      {
throw;
       }
finally
      {
con.Close();
            }
      }

//Event on Add Button….//

private void btnAdd_Click(object sender, EventArgs e)
    {
if (txtCounterId.Text == “” || cboCounterName.Text== “”)
          {
MessageBox.Show(“Counter Id or Name Missing.”,”Important Notice”,MessageBoxButtons.OK,MessageBoxIcon.Exclamation,MessageBoxDefaultButton.Button1);
          }
else
             {
add();
              }
    }

//Function add……//

public void add()
    {
int i = blu.CreateCounter(txtCounterId.Text, cboCounterName.Text);
if (i > 0)
           {
MessageBox.Show(“Create Counter”);
           }
else
          {
MessageBox.Show(“Cannot create Counter”);
         }
    }