datagirdview 的 cellpainting事件如何触发

Question

请教各位一个问题，我想对datagirdview进行单元格合并，网上有很多代码，大多数都利用dataGridView1_CellPainting来实现。
例如下面的代码：
 private void dataGridView1_CellFormatting(object sender, System.Windows.Forms.DataGridViewCellFormattingEventArgs e)
{
    if (this.dataGridView1.Columns["description"].Index == e.ColumnIndex && e.RowIndex >= 0)
    {
        if (this.nextcol != null & e.ColumnIndex == this.nextcol)
        {
            e.CellStyle.BackColor = Color.LightBlue;
            this.nextcol = null;
        }
        if (this.nextrow != null & e.RowIndex == nextrow)
        {
            e.CellStyle.BackColor = Color.LightPink;
            this.nextrow = null;
        }
        if (e.RowIndex != this.dataGridView1.RowCount - 1)
        {
            if (e.Value.ToString() == this.dataGridView1.Rows[e.RowIndex + 1].Cells[e.ColumnIndex].Value.ToString())
            {
                e.CellStyle.BackColor = Color.LightPink;
                nextrow = e.RowIndex + 1;
            }
        } 但是如何调用该事件，或者说该事件如何触发呢？有的说是在datagirdview添加数据的时候自动触发，可是我试过了，并没有触发啊？如果是调用，那么 这个 sender和参数e如何指定呢？

Answer 1

不用你自己调用，CellFormatting是datagridview的事件，写上就好了，双击事件属性，你在里面添加代码就行了

Answer 2

  请教各位，上述问题应该怎样解决，我也遇到了类似的问题。我是从数据库中加载数据到GridView控件上，同时实现表格合并，但是加载数据没问题，但是合并表格的事件并没有触发。代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;
using System.Data.SqlClient;namespace test28
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }        private void button1_Click(object sender, EventArgs e)
        {
            LoadData();
        }        private void LoadData() 
        {
            string connStr = "server=localhost;Trusted_Connection=yes;database=test1";
            string commStr = "select * from test1";            SqlDataAdapter dataAdapter = new SqlDataAdapter(commStr, connStr);
            DataSet dataSet = new DataSet();
            dataAdapter.Fill(dataSet, "test1");
            DataTable dataTable = new DataTable();
            dataTable = dataSet.Tables[0];            this.dataGridView1.DataSource = dataTable;
        }        private void dataGridView1_CellPainting(object sender, System.Windows.Forms.DataGridViewCellPaintingEventArgs e)
        {
            //对第一列单元格进行合并
            if(e.ColumnIndex == 1 && e.RowIndex != -1) {
                using(
                        Brush gridBrush = new SolidBrush(this.dataGridView1.GridColor), backColorBrush = new SolidBrush(e.CellStyle.BackColor)
                     ) {
                         using(
                                Pen gridLinePen = new Pen(gridBrush)
                               ) {
                                    //清除单元格
                                    e.Graphics.FillRectangle(backColorBrush, e.CellBounds);
 
                                    //画Grid边线（仅画单元格的底边线和右边线）
                                    //如果下一行和当前行的数据不同，则在当前的单元格画一条底边线
                                    if(
                                        e.RowIndex < dataGridView1.Rows.Count-2 
                                        && 
                                        dataGridView1.Rows[e.RowIndex + 1].Cells[e.ColumnIndex].Value.ToString() != e.Value.ToString()
                                    ) {
                                        e.Graphics.DrawLine(gridLinePen, e.CellBounds.Left,  e.CellBounds.Bottom-1, e.CellBounds.Right-1, e.CellBounds.Bottom-1); 
                                       }                                        //画右边线
                                        e.Graphics.DrawLine(gridLinePen, e.CellBounds.Right - 1, e.CellBounds.Top, e.CellBounds.Right-1, e.CellBounds.Bottom);                                        //画(填写)单元格内容，相同的内容的单元格只填写第一个
                                        if(e.Value != null) {
                                            if (
                                                e.RowIndex > 0
                                                &&
                                                dataGridView1.Rows[e.RowIndex - 1].Cells[e.ColumnIndex].Value.ToString() == e.Value.ToString()
                                            )
                                            {                                            }
                                                else {
                                                    e.Graphics.DrawString(
                                                        (string)e.Value, 
                                                        e.CellStyle.Font, 
                                                        Brushes.Black, 
                                                        e.CellBounds.X + 2, 
                                                        e.CellBounds.Y + 5, 
                                                        StringFormat.GenericDefault
                                                     );
                                                }                
                                            }
                                    }                        e.Handled = true;
                }
            }
        }
    }
}

Answer 3

有答案吗?我在做控件时也碰到类似问题,我重画oncellpaintting,因没有办法刷新oncellpaintting,出现画出来的单元格叠加残影,能否告之