Recorer checkbox en gridview

gistfile1.cs

// http://www.codeproject.com/KB/webforms/SelChkboxesDataGridView.aspx

for (int i = 0; i < GridView1.Rows.Count; i++)
{
  GridViewRow row = GridView1.Rows[i];
  bool isChecked = ((CheckBox) row.FindControl("chkSelect")).Checked;

  if (isChecked)
  {
    // Column 2 is the name column

    str.Append(GridView1.Rows[i].Cells[2].Text);
  }
}