StaffPerformance/wispro.sp.winClient/HtmlToRtfConverter.cs

using System.Windows.Forms;
using System.Text.RegularExpressions;
using System.Web;
using System.Drawing;
using System;
using System.Linq;

namespace wispro.sp.winClient
{
  
    public class HtmlToRtfConverter
    {
        public string ConvertHtmlToRtf(string html)
        {
            try
            {
                using (RichTextBox rtBox = new RichTextBox())
                {
                    string decodedHtml = HttpUtility.HtmlDecode(html);
                    ProcessHtmlContent(rtBox, decodedHtml);
                    return rtBox.Rtf;
                }
            }
            catch (Exception ex)
            {
                throw new Exception($"HTML转RTF时发生错误: {ex.Message}");
            }
        }

        private void ProcessHtmlContent(RichTextBox rtBox, string html)
        {
            // 首先处理段落
            var paragraphs = Regex.Split(html, @"</?p>")
                                 .Where(p => !string.IsNullOrWhiteSpace(p));

            foreach (var paragraph in paragraphs)
            {
                // 处理段落内的内联元素
                ProcessInlineElements(rtBox, paragraph);

                // 在段落后添加换行
                if (!rtBox.Text.EndsWith(Environment.NewLine))
                {
                    rtBox.AppendText(Environment.NewLine);
                }
            }
        }

        private void ProcessInlineElements(RichTextBox rtBox, string html)
        {
            // 匹配内联元素，包括strike、u标签和br标签
            string pattern = @"<(?<tag>strike|u)[^>]*style=['""](?<style>[^'""]*)['""]>(?<text>[^<]*)</\k<tag>>|<br\s*/>|(?<text>[^<]+)";

            int lastIndex = 0;
            foreach (Match match in Regex.Matches(html, pattern))
            {
                // 处理标签之间的纯文本
                int textStart = match.Index;
                if (textStart > lastIndex)
                {
                    string plainText = html.Substring(lastIndex, textStart - lastIndex);
                    if (!string.IsNullOrWhiteSpace(plainText))
                    {
                        rtBox.AppendText(plainText);
                    }
                }

                string tag = match.Groups["tag"].Value;
                string style = match.Groups["style"].Value;
                string text = match.Groups["text"].Value;

                if (match.Value.StartsWith("<br"))
                {
                    // 处理换行标签
                    rtBox.AppendText(Environment.NewLine);
                }
                else if (!string.IsNullOrEmpty(tag))
                {
                    // 处理格式化标签
                    ApplyFormatting(rtBox, tag, style, text);
                }
                else if (!string.IsNullOrEmpty(text))
                {
                    // 处理纯文本
                    rtBox.AppendText(text);
                }

                lastIndex = match.Index + match.Length;
            }

            // 处理剩余的文本
            if (lastIndex < html.Length)
            {
                string remainingText = html.Substring(lastIndex);
                if (!string.IsNullOrWhiteSpace(remainingText))
                {
                    rtBox.AppendText(remainingText);
                }
            }
        }

        private void ApplyFormatting(RichTextBox rtBox, string tag, string style, string text)
        {
            // 保存当前的格式设置
            Font originalFont = rtBox.SelectionFont ?? rtBox.Font;
            Color originalColor = rtBox.SelectionColor;

            // 设置字体样式
            FontStyle fontStyle = FontStyle.Regular;
            Color textColor = originalColor;

            // 根据标签和样式设置格式
            if (tag == "strike" || style.Contains("line-through"))
            {
                fontStyle |= FontStyle.Strikeout;
            }
            if (tag == "u" || style.Contains("underline"))
            {
                fontStyle |= FontStyle.Underline;
            }

            // 处理颜色
            var colorMatch = Regex.Match(style, @"color:\s*([^;]+)");
            if (colorMatch.Success)
            {
                try
                {
                    string colorValue = colorMatch.Groups[1].Value.Trim();
                    textColor = ColorTranslator.FromHtml(colorValue);
                }
                catch { /* 忽略无效的颜色值 */ }
            }

            // 应用格式
            rtBox.SelectionStart = rtBox.TextLength;
            rtBox.SelectionLength = 0;
            rtBox.SelectionFont = new Font(originalFont.FontFamily, originalFont.Size, fontStyle);
            rtBox.SelectionColor = textColor;

            // 添加文本
            rtBox.AppendText(text);

            // 恢复原始格式
            rtBox.SelectionFont = originalFont;
            rtBox.SelectionColor = originalColor;
        }
    }
}