c# dataGridvew 해더에 체크박스 넣기

private void dataGridview1_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
        {
            if (e.ColumnIndex == 0 && e.RowIndex == -1)
            {
                e.PaintBackground(e.ClipBounds, false);

                Point pt = e.CellBounds.Location;  // where you want the bitmap in the cell

                int nChkBoxWidth = 15;
                int nChkBoxHeight = 15;
                int offsetx = (e.CellBounds.Width - nChkBoxWidth) / 2;
                int offsety = (e.CellBounds.Height - nChkBoxHeight) / 2;

                pt.X += offsetx;
                pt.Y += offsety;

                CheckBox cb = new CheckBox();
                cb.Size = new Size(nChkBoxWidth, nChkBoxHeight);
                cb.Location = pt;
                cb.CheckedChanged += new EventHandler(gvSheetListCheckBox_CheckedChanged);

                ((DataGridView)sender).Controls.Add(cb);

                e.Handled = true;
            }
            
        }

 

 

private void gvSheetListCheckBox_CheckedChanged(object sender, EventArgs e)
        {
            //dataGridview1.ClearSelection();
            //dataGridview1.CommitEdit(DataGridViewDataErrorContexts.Commit);
            //foreach (DataGridViewRow r in dataGridview1.Rows)
            //{
            //    r.Cells[0].Value = ((CheckBox)sender).Checked;
            //}

            dataGridview1.BeginEdit(true);

            foreach (DataGridViewRow item in dataGridview1.Rows)

            {

                item.Cells[0].Value = ((CheckBox)sender).Checked;

            }

            dataGridview1.EndEdit();
        }