htm2txt c#源代码（转载）-优快云博客

本文介绍了一个简单的C#程序，该程序能够将HTML格式的文本转换为纯文本格式，通过去除HTML标签并替换特殊字符，使文本适于在控制台或其他非浏览器环境中显示。

using System;
public class Html2Text
{
    public static void Main(string[] args)
    {
        if (args.Length < 1)
        {
            Console.WriteLine("usage: Htm2Txt xxxx.htm [target.txt]");
        }
        else
        {
            Console.WriteLine(StripHTML("<html><head><title>测试</title></head><body>哈哈</body></html>"));
        }
        char name1=Convert.ToChar("");
        Console.WriteLine("'" + name1 + "'");
    }
    private static string StripHTML(string source)
    {
        try
        {
            string result;

            // Remove HTML Development formatting
            result = source.Replace("/r", " ");        // Replace line breaks with space because browsers inserts space
            result = result.Replace("/n", " ");        // Replace line breaks with space because browsers inserts space
            result = result.Replace("/t", string.Empty);    // Remove step-formatting
            result = System.Text.RegularExpressions.Regex.Replace(result, @"( )+", " ");    // Remove repeating speces becuase browsers ignore them

            // Remove the header (prepare first by clearing attributes)
            result = System.Text.RegularExpressions.Regex.Replace(result, @"<( )*head([^>])*>","<head>", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"(<( )*(/)( )*head( )*>)","</head>", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, "(<head>).*(</head>)",string.Empty, System.Text.RegularExpressions.RegexOptions.IgnoreCase);

            // remove all scripts (prepare first by clearing attributes)
            result = System.Text.RegularExpressions.Regex.Replace(result, @"<( )*script([^>])*>","<script>", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"(<( )*(/)( )*script( )*>)","</script>", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            //result = System.Text.RegularExpressions.Regex.Replace(result, @"(<script>)([^(<script>/.</script>)])*(</script>)",string.Empty, System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"(<script>).*(</script>)",string.Empty, System.Text.RegularExpressions.RegexOptions.IgnoreCase);

            // remove all styles (prepare first by clearing attributes)
            result = System.Text.RegularExpressions.Regex.Replace(result, @"<( )*style([^>])*>","<style>", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"(<( )*(/)( )*style( )*>)","</style>", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, "(<style>).*(</style>)",string.Empty, System.Text.RegularExpressions.RegexOptions.IgnoreCase);

            // insert tabs in spaces of <td> tags
            result = System.Text.RegularExpressions.Regex.Replace(result, @"<( )*td([^>])*>","/t", System.Text.RegularExpressions.RegexOptions.IgnoreCase);

            // insert line breaks in places of <BR> and <LI> tags
            result = System.Text.RegularExpressions.Regex.Replace(result, @"<( )*br( )*>","/r", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"<( )*li( )*>","/r", System.Text.RegularExpressions.RegexOptions.IgnoreCase);

            // insert line paragraphs (double line breaks) in place if <P>, <DIV> and <TR> tags
            result = System.Text.RegularExpressions.Regex.Replace(result, @"<( )*div([^>])*>","/r/r", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"<( )*tr([^>])*>","/r/r", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"<( )*p([^>])*>","/r/r", System.Text.RegularExpressions.RegexOptions.IgnoreCase);

            // Remove remaining tags like <a>, links, images, comments etc - anything thats enclosed inside < >
            result = System.Text.RegularExpressions.Regex.Replace(result, @"<[^>]*>",string.Empty, System.Text.RegularExpressions.RegexOptions.IgnoreCase);

            // replace special characters:
            result = System.Text.RegularExpressions.Regex.Replace(result, @" "," ", System.Text.RegularExpressions.RegexOptions.IgnoreCase);

            result = System.Text.RegularExpressions.Regex.Replace(result, @"•"," * ", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"&lsaquo;","<", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"&rsaquo;",">", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"™","(tm)", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"&frasl;","/", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"<","<", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @">",">", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"©","(c)", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, @"®","(r)", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            // Remove all others. More can be added, see http://hotwired.lycos.com/webmonkey/reference/special_characters/
            result = System.Text.RegularExpressions.Regex.Replace(result, @"&(.{2,6});",string.Empty, System.Text.RegularExpressions.RegexOptions.IgnoreCase);

            // for testng
            //System.Text.RegularExpressions.Regex.Replace(result, this.txtRegex.Text,string.Empty, System.Text.RegularExpressions.RegexOptions.IgnoreCase);

            // make line breaking consistent
            result = result.Replace("/n", "/r");

            // Remove extra line breaks and tabs: replace over 2 breaks with 2 and over 4 tabs with 4.
            // Prepare first to remove any whitespaces inbetween the escaped characters and remove redundant tabs inbetween linebreaks
            result = System.Text.RegularExpressions.Regex.Replace(result, "(/r)( )+(/r)","/r/r", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, "(/t)( )+(/t)","/t/t", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, "(/t)( )+(/r)","/t/r", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, "(/r)( )+(/t)","/r/t", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            result = System.Text.RegularExpressions.Regex.Replace(result, "(/r)(/t)+(/r)","/r/r", System.Text.RegularExpressions.RegexOptions.IgnoreCase);    // Remove redundant tabs
            result = System.Text.RegularExpressions.Regex.Replace(result, "(/r)(/t)+","/r/t", System.Text.RegularExpressions.RegexOptions.IgnoreCase);        // Remove multible tabs followind a linebreak with just one tab
            string breaks = "/r/r/r";        // Initial replacement target string for linebreaks
            string tabs = "/t/t/t/t/t";        // Initial replacement target string for tabs
            for (int index=0; index<result.Length; index++)
            {
                result = result.Replace(breaks, "/r/r");
                result = result.Replace(tabs, "/t/t/t/t");
                breaks = breaks + "/r";
                tabs = tabs + "/t";
            }
            return result;
        }
        catch
        {
        }
        return source;
    }
};