C#

FileStream fs = new FileStream(infile, FileMode.Open, FileAccess.ReadWrite, FileShare.None);

ConnectionOptions conn = new ConnectionOptions();
conn.Impersonation = ImpersonationLevel.Impersonate;
conn.EnablePrivileges = true;

ConnectionOptions conn = new ConnectionOptions();
conn.Authentication = AuthenticationLevel.Default;
conn.Impersonation = ImpersonationLevel.Impersonate;
conn.Username = "DOMAIN\USERNAME";
conn.Password = "PASSWORD";
conn.Authority = null;
conn.EnablePrivileges = true;

conn.Authority = "ntlmdomain:DOMAIN";

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
    ComboBox cbo = e.Control as ComboBox;
    if (cbo != null)
    {
        cbo.SelectionChangeCommitted += new EventHandler(cbo_SelectionChangeCommitted);
    }
}

private void cbo_SelectionChangeCommitted(object sender, EventArgs e)
{
        MessageBox.Show(((ComboBox)sender).Text.ToString());
}