啥？客户叫在DataGridView的左上角添加CheckBox?

效果图是这样的，如何把CheckBox放到左上角是最重要的。

添加

class DatagridViewCheckBoxHeaderCell : DataGridViewColumnHeaderCell
        {
            Point checkBoxLocation;
            Size checkBoxSize;
            bool _checked = false;
            Point _cellLocation = new Point();
            System.Windows.Forms.VisualStyles.CheckBoxState _cbState = System.Windows.Forms.VisualStyles.CheckBoxState.UncheckedNormal;

            public event CheckBoxClickedHandler OnCheckBoxClicked;

            public DatagridViewCheckBoxHeaderCell()
            {
            }

            protected override void Paint(System.Drawing.Graphics graphics,
                System.Drawing.Rectangle clipBounds,
                System.Drawing.Rectangle cellBounds,
                int rowIndex,
                DataGridViewElementStates dataGridViewElementState,
                object value,
                object formattedValue,
                string errorText,
                DataGridViewCellStyle cellStyle,
                DataGridViewAdvancedBorderStyle advancedBorderStyle,
                DataGridViewPaintParts paintParts)
            {
                base.Paint(graphics, clipBounds, cellBounds, rowIndex,
                    dataGridViewElementState, value,
                    formattedValue, errorText, cellStyle,
                    advancedBorderStyle, paintParts);
                Point p = new Point();
                Size s = CheckBoxRenderer.GetGlyphSize(graphics,
                System.Windows.Forms.VisualStyles.CheckBoxState.UncheckedNormal);
                p.X = cellBounds.Location.X +
                    (cellBounds.Width / ) - (s.Width / );
                p.Y = cellBounds.Location.Y +
                    (cellBounds.Height / ) - (s.Height / );
                _cellLocation = cellBounds.Location;
                checkBoxLocation = p;
                checkBoxSize = s;
                if (_checked)
                    _cbState = System.Windows.Forms.VisualStyles.
                        CheckBoxState.CheckedNormal;
                else
                    _cbState = System.Windows.Forms.VisualStyles.
                        CheckBoxState.UncheckedNormal;
                CheckBoxRenderer.DrawCheckBox
                (graphics, checkBoxLocation, _cbState);
            }

            protected override void OnMouseClick(DataGridViewCellMouseEventArgs e)
            {
                Point p = new Point(e.X + _cellLocation.X, e.Y + _cellLocation.Y);
                if (p.X >= checkBoxLocation.X && p.X <=
                    checkBoxLocation.X + checkBoxSize.Width
                && p.Y >= checkBoxLocation.Y && p.Y <=
                    checkBoxLocation.Y + checkBoxSize.Height)
                {
                    _checked = !_checked;
                    if (OnCheckBoxClicked != null)
                    {
                        OnCheckBoxClicked(_checked);
                        this.DataGridView.InvalidateCell(this);
                    }

                }
                base.OnMouseClick(e);
            }
        }

添加方法 InitColumnInfo() 方法，代码如下。

 private void InitColumnInfo()
        {
            int index = ;

            DataGridViewCheckBoxColumn colCB = new DataGridViewCheckBoxColumn();
            DatagridViewCheckBoxHeaderCell cbHeader = new DatagridViewCheckBoxHeaderCell();
            colCB.HeaderCell = cbHeader;
            colCB.HeaderText = "";
            colCB.FillWeight = ;
            cbHeader.OnCheckBoxClicked += new CheckBoxClickedHandler(cbHeader_OnCheckBoxClicked);
            dataGridView2.Columns.Insert(index, colCB);

            System.Windows.Forms.DataGridViewCellStyle dataGridViewCellStyle2 = new System.Windows.Forms.DataGridViewCellStyle();
            dataGridViewCellStyle2.Alignment = System.Windows.Forms.DataGridViewContentAlignment.MiddleCenter;//211, 223, 240
            dataGridViewCellStyle2.ForeColor = System.Drawing.Color.Blue;
            dataGridViewCellStyle2.SelectionForeColor = System.Drawing.Color.Blue;
            dataGridView2.Columns[index].DefaultCellStyle = dataGridViewCellStyle2;
        }

在Clicked事件中添加代码

private void cbHeader_OnCheckBoxClicked(bool state)
        {
            //这一句很重要结束编辑状态
            dataGridView2.EndEdit();
            dataGridView2.Rows.OfType<DataGridViewRow>().ToList().ForEach(t => t.Cells[].Value = state);
        }

最后在窗体的Load事件中，调用 InitColumnInfo() 方法就可以了。