Get The Value From DataGridView To TextBox On c#

Get the value from DataGridView to TextBox on c#. TextBox event in DataGridView in c#.

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;

namespace GirdViewTextBoxEvent

{
    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)

        {

            var txtBox = e.Control as TextBox;

            if (txtBox != null)

            {

                txtBox.Leave += new EventHandler(txtBox_Leave);

            }

        }

        void txtBox_Leave(object sender, EventArgs e)

        {

           
try

            {

                for (int i = 0; i < dataGridView1.Rows.Count; i++)

                {

                    int a = 0, b = 0, c = 0;

                    a = Convert.ToInt32(dataGridView1.Rows[i].Cells["txtRate"].Value);

                    b = Convert.ToInt32(dataGridView1.Rows[i].Cells["txtQuantity"].Value);

                    c = a * b;

                    dataGridView1.Rows[i].Cells["txtTotal"].Value = c;

                }

            }

            catch (Exception ex)

            {

                MessageBox.Show(ex.Message.ToString());

            }

        }

    }

}