DataGridView的paint方法来绘制一行”假”Row来显示(转)

我们在用DataGridView显示数据的时候是否有时会觉得它的功能并不是十分的人性，比如我们想做一个统计所有数据的量或者一列数据的综合，总感到没有地方来呈现它们，其实我们那可以很好的利用DataGridView的paint方法来绘制一行”假”Row来显示，这样既节省空间又美观大方。

首先我们要继承.net自带的强大的DataGridView

1.     提供一个枚举类型BottomAlign用来显示相关值排列的对齐方式(left,right,center),并且在类中定义一个BottomAlign类型的BottomAlignment属性

2.     重写DataGridView的OnPaint方法

具体代码如下:

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Drawing;
using System.ComponentModel;

namespace RaxComponent
...{
    public enum BottomAlign ...{ left, right, center }

    public class RaxDataGridView : DataGridView
    ...{
        private BottomAlign _BottomAlignment = BottomAlign.left;
        [Category("Rax")]
        public BottomAlign BottomAlignment
        ...{
            get
            ...{
                return _BottomAlignment;
            }
            set
            ...{
                _BottomAlignment = value;
            }
        }

        protected override void OnPaint(PaintEventArgs e)
        ...{
            base.OnPaint(e);
            Graphics g;
            if (e == null)
            ...{
                g = Graphics.FromHwnd(this.Handle);
            }
            else
            ...{
                g = e.Graphics;
            }
            SolidBrush myBrush1 = new SolidBrush(SystemColors.Control);
            SolidBrush myBrush2 = new SolidBrush(Color.IndianRed);
            Pen pen1 = new Pen(Brushes.White, 1);
            if (this.Rows.Count > 0 && this.Rows[this.Rows.Count - 1].Displayed)
            ...{
                int LocY = this.GetRowDisplayRectangle(this.Rows.Count - 1, true).Location.Y + this.Rows[this.Rows.Count - 1].Height;
                //draw caption
                g.FillRectangle(myBrush1, 2, LocY, this.RowHeadersWidth - 2, 23);
                //caption's top line
                g.DrawLine(pen1, new Point(2, LocY), new Point(this.RowHeadersWidth - 1, LocY));
                // caption's left line
                g.DrawLine(pen1, new Point(2, LocY), new Point(2, LocY + 23));

                //draw cells
                StringFormat sf = new StringFormat();
                sf.Alignment = StringAlignment.Near;
                sf.LineAlignment = StringAlignment.Near;

                int cellLocX = this.RowHeadersWidth + 1;
                int i = this.Columns.Count;
                for (int j = 0; j < i; j++)
                ...{
                    if (this.Columns[j].Displayed)
                    ...{
                        int cellTextLocX = cellLocX;
                        g.FillRectangle(myBrush2, cellLocX, LocY, this.GetColumnDisplayRectangle(j, false).Width - 1, 23);
                        DrawString#region DrawString
                        if (this.GetColumnDisplayRectangle(j, false).Width == this.Columns[j].Width)
                        ...{
                            int cellWidth = this.GetColumnDisplayRectangle(j, false).Width;
                            try
                            ...{
                                string strFmValue = this.Columns[j].DataPropertyName + "列相关值";
                                switch (this.BottomAlignment)
                                ...{
                                    case BottomAlign.right:
                                        cellTextLocX = cellTextLocX + cellWidth - (int)g.MeasureString(strFmValue, new Font(new FontFamily("Verdana"), 8), cellWidth).Width;
                                        break;
                                    case BottomAlign.center:
                                        cellTextLocX = cellTextLocX + cellWidth / 2 - (int)(g.MeasureString(strFmValue, new Font(new FontFamily("Verdana"), 8), cellWidth).Width / 2);
                                        break;
                                }
                                g.DrawString(strFmValue, new Font(new FontFamily("Verdana"), 8), Brushes.Black, cellTextLocX, LocY + 6, sf);
                            }
                            catch
                            ...{
                                g.DrawString("", new Font(new FontFamily("Verdana"), 8), Brushes.Black, cellTextLocX, LocY + 6, sf);
                            }
                        }
                        #endregion
                        cellLocX += this.GetColumnDisplayRectangle(j, false).Width;
                    }
                }
                // draw caption string
                g.DrawString("Rax", new Font(new FontFamily("Verdana"), 8), Brushes.Black, 4, LocY + 6, sf);
            }
        }
    }
}