สอบถามเรื่องการ find control checkbox ใน datagridview หน่อยครับ

foreach (DataGridViewRow dr in dataGridView1.Rows)
            {
                if (dr.Cells[0].Value != null)
                {
                    lisQuery.Items.Add(dataGridView1["ITEMS", dr.Index].Value.ToString());
                }
            }

for (i = 0; i <= this.dgStock.BindingContext[dgStock.DataSource].Count - 1; i++)
{
if (this.dgStock[i, 1].ToString().Trim() != "")
{
    strAssetID = this.dgStock[i, 1].ToString();
    if (strAssetID != "")
    {
	Console.WriteLine(strAssetID);
    }
  }
}

         foreach (DataGridViewRow dr in dataGridView1.Rows)
            {
                if (dr.Cells[0].Value != null)
                {

                    exSheet.Cells[ctn + 7, 1] = ds.Tables["ITEMS"].Rows[ctn][0].ToString();
                    exSheet.Cells[ctn + 7, 2] = ds.Tables["ITEMS"].Rows[ctn][1].ToString();
                    exSheet.Cells[ctn + 7, 3] = ds.Tables["ITEMS"].Rows[ctn][2].ToString();
                    countendcell = (ctn + 7) + 1;
                    ctn++;
                }
            }

DataGridViewCheckBoxColumn CheckBoxColumn = new DataGridViewCheckBoxColumn();
CheckBoxColumn.ReadOnly = false;
CheckBoxColumn.DisplayIndex = 0;
CheckBoxColumn.DefaultCellStyle.BackColor = System.Drawing.Color.LightGray;
CheckBoxColumn.TrueValue = true;
CheckBoxColumn.FalseValue = false;
CheckBoxColumn.Width = 20;

dataGridView1.Columns.Add(CheckBoxColumn);

foreach (DataGridViewRow row in dataGridView1.Rows)
{
      if (Convert.ToBoolean(row.Cells[0].Value) == true)
            //do something
      }
 }

foreach (DataGridViewRow row in dataGridView1.Rows)
{
      DataGridViewCheckBoxCell CheckBoxCell = (DataGridViewCheckBoxCell)row.Cells[0];

      if (Convert.ToBoolean(CheckBoxCell.Value) == true)
            //do something
      }
}