代码分享，WinForm中LinkLabel实现关键字高亮


使用说明：

IgnoreCase 是否匹配大小写，默认false，严格匹配大小写

Keyword 关键字

KeywordColor 关键字的颜色，默认红色

BUG列表：

部分颜色属性不工作，比如访问后颜色，自定义背景色等等

不支持多行文本

代码：

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

namespace WindowsFormsApplication1
{
    class SuperLinkLabel : LinkLabel
    {
        public bool IgnoreCase { get; set; }

        private string keyWord = "";
        public string Keyword
        {
            get { return keyWord; }
            set { keyWord = value; this.Invalidate(); }
        }

        public Color KeywordColor { get; set; }

        public SuperLinkLabel()
        {
            Keyword = "";
            KeywordColor = Color.Red;
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            e.Graphics.FillRectangle(new SolidBrush(SystemColors.Control), e.ClipRectangle);

            StringFormat stringFormat = new StringFormat();
            stringFormat.SetMeasurableCharacterRanges(GetRanges());
            stringFormat.FormatFlags = StringFormatFlags.MeasureTrailingSpaces;
            Region[] regions = e.Graphics.MeasureCharacterRanges(Text, Font, new RectangleF(e.ClipRectangle.X, e.ClipRectangle.Y, e.ClipRectangle.Width + 200, e.ClipRectangle.Height), stringFormat); 
 

            int i = 0;
            foreach (var item in GetStringRgn().ToList())
            {
                bool isKeyword = GetStringRgn().Single(x => x.Item1 == item.Item1).Item3;
                e.Graphics.DrawString(Text.Substring(item.Item1, item.Item2 - item.Item1 + 1), Font, isKeyword ? new SolidBrush(KeywordColor) : new SolidBrush(LinkColor), new PointF(regions[i].GetBounds(e.Graphics).X, regions[i].GetBounds(e.Graphics).Y), stringFormat);
                i++;
            }
        }

        private CharacterRange[] GetRanges()
        {
            return GetStringRgn().ToArray().Select(x => new CharacterRange(x.Item1, x.Item2 - x.Item1 + 1)).ToArray();
        }

        private IEnumerable<Tuple<int, int, bool>> GetStringRgn()
        {
            if (Keyword == "" || Text == "")
            {
                if (Text == "") yield break;
                yield return new Tuple<int, int, bool>(0, Text.Length - 1, false);
                yield break;
            }
            int pre = 0;
            int i = 0;
            while (i <= Text.Length - Keyword.Length)
            { 
 
                if (Text.Substring(i, Keyword.Length).ToUpper() == Keyword.ToUpper())
                {
                    if (IgnoreCase || Text.Substring(i, Keyword.Length) == Keyword)
                    {
                        if (pre != i) yield return new Tuple<int, int, bool>(pre, i - 1, false);
                        yield return new Tuple<int, int, bool>(i, i + Keyword.Length - 1, true);
                        i += Keyword.Length;
                        pre = i;
                    }
                    else
                    {
                        i++;
                    }
                }
                else
                {
                    i++;
                }
            }
            if (pre <= Text.Length - 1) yield return new Tuple<int, int, bool>(pre, Text.Length - 1, false); 
 
        }
    }
}

最后show下VS2013

[解决办法]

[解决办法]
msdn上说的是32个“character ranges”，不是32个字符，我试了下确实是这样的。