for (int i = 0; i <= dgList.Rows.Count - 1; i++)
{
DataGridViewComboBoxCell cell = dgList.Rows[i].Cells[0] as DataGridViewComboBoxCell;
string strVal = cell.Value.ToString();
string strtext = cell.OwningColumn.HeaderText();
}
OR
for (int i = 0; i <= dgList.Rows.Count - 1; i++)
{
DataGridViewComboBoxCell cell = dgList.Rows[i].Cells[0] as DataGridViewComboBoxCell;
string strVal = cell.Value.ToString();
string strtext = cell.FormattedValue.ToString();
}