帶CheckBox列頭的DataGridView(一)

在項目的開發中，在DataGridView中將CheckBox作爲第一列使用的很平常，使用微軟自帶DataGridView中的DataGridViewCheckBoxCell，但是微軟自帶的DataGridView中又沒有能夠將CheckBox作爲列頭來做全選和全取消選擇的功能。所以如果想實現在列頭上顯示一個CheckBox並且點擊CheckBox來實現全選和全取消，就沒有現成的。但是辦法是人想出來的，既然微軟沒有能夠提供現成的實現方法，那我們就要自己動手，才能豐衣足食了。其實這個功能實現起來也不是很難，我們首先要定義一個DatagridViewCheckBoxHeaderCell類，它是繼承自DataGridViewColumnHeaderCell，主要是要重寫裏面的OnPaint方法和OnMouseClick方法即可，代碼如下：

 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 / 2) - (s.Width / 2);
            p.Y = cellBounds.Location.Y +
                (cellBounds.Height / 2) - (s.Height / 2);
            _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);
        }    

    }

 

除此之外，還需要加上事件處理的委託，代碼如下：

 public delegate void CheckBoxClickedHandler(bool state);
    public class DataGridViewCheckBoxHeaderCellEventArgs : EventArgs
    {
        bool _bChecked;
        public DataGridViewCheckBoxHeaderCellEventArgs(bool bChecked)
        {
            _bChecked = bChecked;
        }
        public bool Checked
        {
            get { return _bChecked; }
        }
    }

然後在客戶端加上如下代碼：

DataGridViewCheckBoxColumn colCB = new DataGridViewCheckBoxColumn();DatagridViewCheckBoxHeaderCell cbHeader =new DatagridViewCheckBoxHeaderCell();colCB.HeaderCell = cbHeader;datagridview1.Columns.Add(colCB);

再在客戶端完成事件處理：

cbHeader.OnCheckBoxClicked +=     new CheckBoxClickedHandler(cbHeader_OnCheckBoxClicked);

主要的代碼實現就這麼多呢。

爲了方便大家的使用，我做了一個Demo來演示具體怎麼使用，可以到我的資源中去下載：http://download.csdn.net/detail/weizhiai12/4445491。

原文的作者沒有提供例子。

想查看原文的可以點擊如下地址查看：

http://www.codeproject.com/Articles/20165/CheckBox-Header-Column-For-DataGridView