Delete multiple rows from DataGridView using CheckBox in Windows Forms Application

I have added a checkbox column to the DataGridView and then written the following code

Namespalces

using System.Data;
using System.Data.SqlClient;

Code

public partial class Form1 : Form
{
    private const string ConnectionString = @"Data Source=.\SQL2008R2;Initial Catalog=AjaxSamples;User id = sa;password=pass@123";
    public Form1()
    {
        InitializeComponent();
        BindGrid();
    }

    private void BindGrid()
    {
        using (SqlConnection con = new SqlConnection(ConnectionString))
        {
            using (SqlCommand cmd = new SqlCommand("SELECT CustomerId, Name, Country FROM Customers", con))
            {
                cmd.CommandType = CommandType.Text;
                using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
                {
                    using (DataTable dt = new DataTable())
                    {
                        sda.Fill(dt);

                        //Set Columns Count
                        dataGridView1.ColumnCount = 3;

                        //Hide the last blank line
                        dataGridView1.AllowUserToAddRows = false;

                        //Add Columns
                        dataGridView1.Columns[0].Name = "CustomerId";
                        dataGridView1.Columns[0].HeaderText = "CustomerId Id";
                        dataGridView1.Columns[0].DataPropertyName = "CustomerId";

                        dataGridView1.Columns[1].HeaderText = "Name";
                        dataGridView1.Columns[1].Name = "Name";
                        dataGridView1.Columns[1].DataPropertyName = "Name";

                        dataGridView1.Columns[2].Name = "Country";
                        dataGridView1.Columns[2].HeaderText = "Country";
                        dataGridView1.Columns[2].DataPropertyName = "Country";

                        DataGridViewCheckBoxColumn checkBoxColumn = new DataGridViewCheckBoxColumn();
                        checkBoxColumn.HeaderText = "";
                        checkBoxColumn.Name = "checkBoxColumn";
                        dataGridView1.Columns.Insert(0, checkBoxColumn);

                        dataGridView1.DataSource = dt;
                    }
                }
            }
        }
    }

    private void btnDelete_Click(object sender, EventArgs e)
    {
        foreach (DataGridViewRow row in dataGridView1.Rows)
        {
            if (Convert.ToBoolean(row.Cells["checkBoxColumn"].Value))
            {
                using (SqlConnection con = new SqlConnection(ConnectionString))
                {
                    using (SqlCommand cmd = new SqlCommand("DELETE FROM Customers WHERE CustomerId = @CustomerId", con))
                    {
                        cmd.CommandType = CommandType.Text;
                        cmd.Parameters.AddWithValue("@CustomerId", row.Cells["CustomerId"].Value);
                        con.Open();
                        cmd.ExecuteNonQuery();
                        con.Close();
                    }
                }
            }
        }
    }
}

Table

DataGridView