optimistic concurrency

I doing a simple example to learn about optimistic concurrency.  

I have a winform app that displays the employees from the northwind database using a datagridview.  The form has a button click handler to update the datagridview.

In my class file, I have a method called RowUpdated that I want to call to check if there have been any changes to datagridview by another user.  How do I invoke the method so it will check any concurrency issues?

Do I need to add an event handler in the page load?

Thanks for any help.

Employee class file:
 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using OptimisticConcurrencyExample.NorthwindTableAdapters;
using System.Data;
using System.Data.SqlClient;
using System.Diagnostics;
 
namespace OptimisticConcurrencyExample
{
    class Employee
    {
        private EmployeesTableAdapter _adapter = null;
 
        public EmployeesTableAdapter adapter
        {
            get
            {
                if (_adapter == null)
                {
                    _adapter = new EmployeesTableAdapter();
                }
                return _adapter;
            }
        }
 
        public Northwind.EmployeesDataTable GetEmployees()
        {
            return adapter.GetEmployees();
        }
 
        public void UpdateDataSet(Northwind.EmployeesDataTable dt)
        {
            NorthwindTableAdapters.EmployeesTableAdapter eta = new EmployeesTableAdapter();
            eta.Update(dt);
 
            try
            {
                foreach (Northwind.EmployeesRow currentRow in dt)
                {
                    if (currentRow.HasErrors == true)
                    {
                        Debug.WriteLine(currentRow.EmployeeID + "\n" + currentRow.RowError.ToString());
                    }
                }
            }
            catch (Exception ex)
            {
                // Log errors here.
            }
        }
 
        public void RowUpdated(object sender, SqlRowUpdatedEventArgs e)
        {
            if (e.RecordsAffected == 0)
            {
                e.Row.RowError = "Another user may have recently modified this row.";
                e.Status = UpdateStatus.SkipCurrentRow;
 
            }
        }
 
    }
}
 
winform code-behind:
 
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 OptimisticConcurrencyExample
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();  
        }
 
        private void Form2_Load(object sender, EventArgs e)
        {
            Employee emp = new Employee();
            gvEmployees.DataSource = emp.GetEmployees();
        }
 
        private void gvEmployees_RowEnter(object sender, DataGridViewCellEventArgs e)
        {
            txtEmployeeID.Text = gvEmployees.Rows[e.RowIndex].Cells[0].Value.ToString();
            txtFirstName.Text = gvEmployees.Rows[e.RowIndex].Cells[2].Value.ToString();
            txtLastName.Text = gvEmployees.Rows[e.RowIndex].Cells[1].Value.ToString();
        }
 
        private void btnUpdate_Click(object sender, EventArgs e)
        {
            Employee emp = new Employee();
            Northwind.EmployeesDataTable dt = new Northwind.EmployeesDataTable();
            dt = (Northwind.EmployeesDataTable)gvEmployees.DataSource;
            emp.UpdateDataSet(dt);
        }
    }
}

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