How to add select all checkbox to DataGridView

//Your DataGridView: dtgrd
//Flag to determine select all or not
bool bSelectAll = false;

if (dtgrd.Controls.Find("chkSelectAll", true).Length > 0)
{
 dtgrd.Controls.RemoveByKey("chkSelectAll");
}
if (dtgrd.Rows.Count > 0)
{
 DataGridViewCheckBoxColumn dtChkCol = new DataGridViewCheckBoxColumn(false);
 dtChkCol.Width = 30;
 dtChkCol.Resizable = DataGridViewTriState.False;
 dtChkCol.ReadOnly = false;
 dtgrd.Columns.Insert(0, dtChkCol);

 Rectangle rect = dtgrd.GetCellDisplayRectangle(0, -1, true);
 rect.X = rect.Location.X + (rect.Width / 3);
 rect.Y = rect.Location.Y + (rect.Height / 3);
 CheckBox chkSelectAll = new CheckBox();
 chkSelectAll.Name = "chkSelectAll";
 chkSelectAll.Size = new Size(18, 18);
 chkSelectAll.Location = rect.Location;
 chkSelectAll.CheckedChanged += new EventHandler(chkSelectAll_CheckedChanged);
 chkSelectAll.Checked = false;
 dtgrd.Controls.Add(chkSelectAll);

 dtgrd.Columns[lcCheck].Frozen = true;
}


//Event here
private void chkSelectAll_CheckedChanged(object sender, EventArgs e)
{
 if (bSelectAll)
 {  
  for (int i = 0; i < dtgrd.Rows.Count; i++)
  {
   dtgrd[lcCheck, i].Value = 0;
  }
  bSelectAll = false;
 }
 else
 {
  for (int i = 0; i < dtgrd.Rows.Count; i++)
  {
   dtgrd[lcCheck, i].Value = 1;
  }
  bSelectAll = true;
 }
 dtgrd.EndEdit();
}