DataGridView合并单元格

昨天一个同事问我DataGridView单元格合并的问题，一开始按照我的设想是算出两个单元格的Rectangle，
然后直接使用e.Graphics.FillRectangle(backColorBrush, rectangle)从新填充下背景色，然后在绘制显示的字符，当然这种想法是行不通的。

下面是我写的一个单元格合并的方法，其实这种方法并不好，只是看上去是把单元格合并了，其实实际DataGridView的列结构是没有发生变化，而且这种重绘的方法并不能编辑，所以我还是建议如果遇到合并单元格的问题，最好还是不要用DataGridView
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代码部分：

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

namespace WindowsDemo
{
    public partial class DataGridViewMergeCell : Form
    {
        public DataGridViewMergeCell()
        {
            InitializeComponent();
            Init();
        }

private void DataGridViewMergeCell_Load(object sender, EventArgs e)
        {
            int rowIndex = view.Rows.Add();
            DataGridViewRow row = view.Rows[rowIndex];
            row.Cells["value"].Value = "bbb";
            row.Cells["name"].Value = "aaa";
            row.Cells["price"].Value = "bbb";
            row.Cells["num"].Value = "aaa";
            rowIndex = view.Rows.Add();
            row = view.Rows[rowIndex];
            row.Cells["value"].Value = "bbb";
            row.Cells["name"].Value = "aaa";
            row.Cells["price"].Value = "bbb";
            row.Cells["num"].Value = "aaa";
            rowIndex = view.Rows.Add();
            row = view.Rows[rowIndex];
            row.Cells["value"].Value = "bbb";
            row.Cells["name"].Value = "aaa";
            row.Cells["price"].Value = "bbb";
            row.Cells["num"].Value = "aaa";
            rowIndex = view.Rows.Add();
            row = view.Rows[rowIndex];
            row.Cells["value"].Value = "bbb";
            row.Cells["name"].Value = "aaa";
            row.Cells["price"].Value = "bbb";
            row.Cells["num"].Value = "aaa";
            rowIndex = view.Rows.Add();
            row = view.Rows[rowIndex];
            row.Cells["value"].Value = "bbb";
            row.Cells["name"].Value = "aaa";
            row.Cells["price"].Value = "bbb";
            row.Cells["num"].Value = "aaa";
           
           
        }

private void Init() {

view.AllowUserToAddRows = false;
            // view.ColumnHeadersVisible = false;
            view.AutoGenerateColumns = false;
            view.AutoSize = false;
            //view.RowHeadersVisible = false;
            //view.GridColor = System.Drawing.ColorTranslator.FromHtml("#F8F8FF");
            view.ColumnHeadersHeight = 60;
           
            view.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.None;
            view.ColumnHeadersBorderStyle = DataGridViewHeaderBorderStyle.Single;
            view.Columns.Add(new DataGridViewTextBoxColumn() { Name = "name", HeaderText = "主体", Width = 90, ReadOnly = true,Visible = true, AutoSizeMode = DataGridViewAutoSizeColumnMode.None });
            view.Columns.Add(new DataGridViewTextBoxColumn() { Name = "value", HeaderText = "", Width = 80, ReadOnly = true, Visible = true, AutoSizeMode = DataGridViewAutoSizeColumnMode.None });
            view.Columns.Add(new DataGridViewTextBoxColumn() { Name = "price", HeaderText = "主体", Width = 90, ReadOnly = true, Visible = true, AutoSizeMode = DataGridViewAutoSizeColumnMode.None });
            view.Columns.Add(new DataGridViewTextBoxColumn() { Name = "num", HeaderText = "", Width = 80, ReadOnly = true, Visible = true, AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill });
            view.CellPainting -= new DataGridViewCellPaintingEventHandler(view_CellPainting);
            view.CellPainting += new DataGridViewCellPaintingEventHandler(view_CellPainting);
        }

void view_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
        {
            if (e.RowIndex == 1 && e.ColumnIndex == 1)
            {
                Brush backColorBrush = new SolidBrush(e.CellStyle.BackColor);
                e.Paint(e.CellBounds, DataGridViewPaintParts.All);
                e.Graphics.FillRectangle(backColorBrush, e.CellBounds);
                //绘制背景色(被选中状态下)  
                if (e.State == (DataGridViewElementStates.Displayed | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible))
                    e.PaintBackground(e.CellBounds, false);
                //分别绘制原文本和现在改变颜色的文本  
                Brush fontColor = new SolidBrush(e.CellStyle.ForeColor);
                // e.Graphics.DrawString("", this.Font, fontColor, e.CellBounds, StringFormat.GenericDefault);
                //绘制下边框线
                Brush gridBrush = new SolidBrush(this.view.GridColor);
                Pen pen = new Pen(gridBrush);
                e.Graphics.DrawLine(pen, e.CellBounds.Left, e.CellBounds.Bottom - 1,
                          e.CellBounds.Right - 1, e.CellBounds.Bottom - 1);
              DataGridViewCell cell =  this.view.Rows[e.RowIndex].Cells[e.ColumnIndex];
                
              cell.Value = "";
              e.Handled = true;
            }
            if (e.RowIndex == 1 && e.ColumnIndex == 2)
            {
                Brush backColorBrush = new SolidBrush(e.CellStyle.BackColor);
                e.Paint(e.CellBounds, DataGridViewPaintParts.All);
                e.Graphics.FillRectangle(backColorBrush, e.CellBounds);
                //绘制背景色(被选中状态下)  
                if (e.State == (DataGridViewElementStates.Displayed | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible))
                    e.PaintBackground(e.CellBounds, true);
                //分别绘制原文本和现在改变颜色的文本  
                Brush fontColor = new SolidBrush(e.CellStyle.ForeColor);
               // e.Graphics.DrawString("", this.Font, fontColor, e.CellBounds, StringFormat.GenericDefault);
                //绘制下边框线
                Brush gridBrush = new SolidBrush(this.view.GridColor);
                Pen pen = new Pen(gridBrush);

e.Graphics.DrawLine(pen, e.CellBounds.Left, e.CellBounds.Bottom - 1,
                          e.CellBounds.Right - 1, e.CellBounds.Bottom - 1);

//绘制右边框线
                e.Graphics.DrawLine(pen, e.CellBounds.Right - 1,
                           e.CellBounds.Top, e.CellBounds.Right - 1,
                           e.CellBounds.Bottom - 1);
                DataGridViewCell cell = this.view.Rows[e.RowIndex].Cells[e.ColumnIndex];
                cell.Value = "";
                cell.Tag = "ccccc";
                Rectangle rectanle = e.CellBounds;
                rectanle.X = rectanle.X -15;
                rectanle.Y = rectanle.Y + 5;
                //这里需要注意的是我没有用 e.Graphics 原因是这个只能在当前单元格绘制
                //而我是在DataGridView上面建一个绘图Graphics对象这样就可以看上去在两个单元格里面绘制了
                //这里你们也可以自己试一试
                Graphics graphics = this.view.CreateGraphics();
                //分别绘制原文本和现在改变颜色的文本  
                graphics.DrawString("cccc", this.Font, new SolidBrush(e.CellStyle.ForeColor), rectanle, StringFormat.GenericDefault);
                e.Handled = true;
            }
        }
    }
}

以下是我的建议，这种虽然看上去是把问题解决了，其实这样有很多缺点，一个是不能编辑，而且这个还有个bug就是点击左边的边框的时候会把左边的文字隐藏起来，我试了很多方法都没解决，这个应该是编辑的时候背景颜色给遮住了。

一下推荐一个可以合并单元格的第三方控件（DevExpress.XtraGrid.v7.3.dll），这个现在我也没有研究，不过后续我会研究的，也会在写篇文章的