datagridview多色文本

我正试图在datagridviewcell中显示多色文本，我几乎做到了。但是在双击列分隔符时发现了一个小问题。

双击列分隔符时，未绘制单元格背景色的一部分正确地我忘记怎么处理我的代码了？请推荐我。

这是我的代码

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 MulticoloredGridViewTest
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            dataGridView1.Rows.Add("niaz,rahim,azme,niaz,rahim,azme", "123,677,111", "dhaka,dhaka,dhaka");
        }
        private void dataGridView1_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
        {
            if (e.RowIndex >= -1)
            {
                // Rectangle newRect = new Rectangle(e.CellBounds.X + 1, e.CellBounds.Y + 1, e.CellBounds.Width - 1, e.CellBounds.Height - 1);
                e.Paint(e.ClipBounds, DataGridViewPaintParts.All & ~DataGridViewPaintParts.ContentForeground);
                StringFormat sf = new StringFormat();
                sf.Alignment = StringAlignment.Center;
                sf.LineAlignment = StringAlignment.Center;
                Point startPoint = e.CellBounds.Location;
                if (e.Value != null)
                {
                    string[] dataList = e.Value.ToString().Split(',');
                    foreach (string data in dataList)
                    {
                        SizeF tmpSize = e.Graphics.MeasureString(data.Trim(), e.CellStyle.Font);
                        Rectangle txtRegion = new Rectangle(startPoint, new Size((int)(tmpSize.Width + 3), e.CellBounds.Height));
                        Color clr = new Color();
                        if (data.Trim().Contains("rahim"))
                            clr = Color.Red;
                        else
                            clr = Color.Black;
                        using (SolidBrush br = new SolidBrush(clr))
                        {
                            e.Graphics.DrawString(data.Trim(), e.CellStyle.Font, br, txtRegion, StringFormat.GenericDefault);
                        }
                        startPoint = new Point(startPoint.X+txtRegion.Width+1, e.CellBounds.Location.Y);
                    }
                    e.Handled = true;
                }
            }
        }
        private void button1_Click(object sender, EventArgs e)
        {
            string[] cell = textBox1.Text.Split(',');
            string value = dataGridView1.Rows[int.Parse(cell[0])].Cells[int.Parse(cell[1])].Value.ToString();
            label1.Text = value;
        }
        private void dataGridView1_ColumnDividerDoubleClick(object sender, DataGridViewColumnDividerDoubleClickEventArgs e)
        {
            dataGridView1.Columns[e.ColumnIndex].DividerWidth = dataGridView1.CurrentCell.Value.ToString().Length + 10;
            dataGridView1.Invalidate();
        }
    }
}

private void btnAutoResizeContactNameColumn_Click(object sender, EventArgs e)
{
// Perform Auto Resize on Contact column
this.ultraGrid1.DisplayLayout.Bands[0].Columns["ContactName"].PerformAutoResize();
}