调用： ClipboardHelper.CopyToClipboard("<h1>hello world</h1>", "");
/// <summary> /// Helper to encode and set HTML fragment to clipboard.<br/> /// See http://theartofdev.com/2014/06/12/setting-htmltext-to-clipboard-revisited/.<br/> /// <seealso cref="CreateDataObject"/>. /// </summary> /// <remarks> /// The MIT License (MIT) Copyright (c) 2014 Arthur Teplitzki. /// </remarks> public static class ClipboardHelper { #region Fields and Consts /// <summary> /// The string contains index references to other spots in the string, so we need placeholders so we can compute the offsets. <br/> /// The <![CDATA[<<<<<<<]]>_ strings are just placeholders. We'll back-patch them actual values afterwards. <br/> /// The string layout (<![CDATA[<<<]]>) also ensures that it can't appear in the body of the html because the <![CDATA[<]]> <br/> /// character must be escaped. <br/> /// </summary> private const string Header = @"Version:0.9 StartHTML:<<<<<<<<1 EndHTML:<<<<<<<<2 StartFragment:<<<<<<<<3 EndFragment:<<<<<<<<4 StartSelection:<<<<<<<<3 EndSelection:<<<<<<<<4"; /// <summary> /// html comment to point the beginning of html fragment /// </summary> public const string StartFragment = "<!--StartFragment-->"; /// <summary> /// html comment to point the end of html fragment /// </summary> public const string EndFragment = @"<!--EndFragment-->"; /// <summary> /// Used to calculate characters byte count in UTF-8 /// </summary> private static readonly char[] _byteCount = new char[1]; #endregion /// <summary> /// Create <see cref="DataObject"/> with given html and plain-text ready to be used for clipboard or drag and drop.<br/> /// Handle missing <![CDATA[<html>]]> tags, specified startend segments and Unicode characters. /// </summary> /// <remarks> /// <para> /// Windows Clipboard works with UTF-8 Unicode encoding while .NET strings use with UTF-16 so for clipboard to correctly /// decode Unicode string added to it from .NET we needs to be re-encoded it using UTF-8 encoding. /// </para> /// <para> /// Builds the CF_HTML header correctly for all possible HTMLs<br/> /// If given html contains start/end fragments then it will use them in the header: /// <code><![CDATA[<html><body><!--StartFragment-->hello <b>world</b><!--EndFragment--></body></html>]]></code> /// If given html contains html/body tags then it will inject start/end fragments to exclude html/body tags: /// <code><![CDATA[<html><body>hello <b>world</b></body></html>]]></code> /// If given html doesn't contain html/body tags then it will inject the tags and start/end fragments properly: /// <code><![CDATA[hello <b>world</b>]]></code> /// In all cases creating a proper CF_HTML header:<br/> /// <code> /// <![CDATA[ /// Version:1.0 /// StartHTML:000000177 /// EndHTML:000000329 /// StartFragment:000000277 /// EndFragment:000000295 /// StartSelection:000000277 /// EndSelection:000000277 /// <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> /// <html><body><!--StartFragment-->hello <b>world</b><!--EndFragment--></body></html> /// ]]> /// </code> /// See format specification here: http://msdn.microsoft.com/library/default.asp?url=/workshop/networking/clipboard/htmlclipboard.asp /// </para> /// </remarks> /// <param name="html">a html fragment</param> /// <param name="plainText">the plain text</param> public static DataObject CreateDataObject(string html, string plainText) { html = html ?? String.Empty; var htmlFragment = GetHtmlDataString(html); // re-encode the string so it will work correctly (fixed in CLR 4.0) if (Environment.Version.Major < 4 && html.Length != Encoding.UTF8.GetByteCount(html)) htmlFragment = Encoding.Default.GetString(Encoding.UTF8.GetBytes(htmlFragment)); var dataObject = new DataObject(); dataObject.SetData(DataFormats.Html, htmlFragment); dataObject.SetData(DataFormats.Text, plainText); dataObject.SetData(DataFormats.UnicodeText, plainText); return dataObject; } /// <summary> /// Clears clipboard and sets the given HTML and plain text fragment to the clipboard, providing additional meta-information for HTML.<br/> /// See <see cref="CreateDataObject"/> for HTML fragment details.<br/> /// </summary> /// <example> /// ClipboardHelper.CopyToClipboard("Hello <b>World</b>", "Hello World"); /// </example> /// <param name="html">a html fragment</param> /// <param name="plainText">the plain text</param> public static void CopyToClipboard(string html, string plainText) { var dataObject = CreateDataObject(html, plainText); Clipboard.SetDataObject(dataObject, true); } /// <summary> /// Generate HTML fragment data string with header that is required for the clipboard. /// </summary> /// <param name="html">the html to generate for</param> /// <returns>the resulted string</returns> private static string GetHtmlDataString(string html) { var sb = new StringBuilder(); sb.AppendLine(Header); sb.AppendLine(@"<!DOCTYPE HTML PUBLIC ""-//W3C//DTD HTML 4.0 Transitional//EN"">"); // if given html already provided the fragments we won't add them int fragmentStart, fragmentEnd; int fragmentStartIdx = html.IndexOf(StartFragment, StringComparison.OrdinalIgnoreCase); int fragmentEndIdx = html.LastIndexOf(EndFragment, StringComparison.OrdinalIgnoreCase); // if html tag is missing add it surrounding the given html (critical) int htmlOpenIdx = html.IndexOf("<html", StringComparison.OrdinalIgnoreCase); int htmlOpenEndIdx = htmlOpenIdx > -1 ? html.IndexOf('>', htmlOpenIdx) + 1 : -1; int htmlCloseIdx = html.LastIndexOf("</html", StringComparison.OrdinalIgnoreCase); if (fragmentStartIdx < 0 && fragmentEndIdx < 0) { int bodyOpenIdx = html.IndexOf("<body", StringComparison.OrdinalIgnoreCase); int bodyOpenEndIdx = bodyOpenIdx > -1 ? html.IndexOf('>', bodyOpenIdx) + 1 : -1; if (htmlOpenEndIdx < 0 && bodyOpenEndIdx < 0) { // the given html doesn't contain html or body tags so we need to add them and place start/end fragments around the given html only sb.Append("<html><body>"); sb.Append(StartFragment); fragmentStart = GetByteCount(sb); sb.Append(html); fragmentEnd = GetByteCount(sb); sb.Append(EndFragment); sb.Append("</body></html>"); } else { // insert start/end fragments in the proper place (related to html/body tags if exists) so the paste will work correctly int bodyCloseIdx = html.LastIndexOf("</body", StringComparison.OrdinalIgnoreCase); if (htmlOpenEndIdx < 0) sb.Append("<html>"); else sb.Append(html, 0, htmlOpenEndIdx); if (bodyOpenEndIdx > -1) sb.Append(html, htmlOpenEndIdx > -1 ? htmlOpenEndIdx : 0, bodyOpenEndIdx - (htmlOpenEndIdx > -1 ? htmlOpenEndIdx : 0)); sb.Append(StartFragment); fragmentStart = GetByteCount(sb); var innerHtmlStart = bodyOpenEndIdx > -1 ? bodyOpenEndIdx : (htmlOpenEndIdx > -1 ? htmlOpenEndIdx : 0); var innerHtmlEnd = bodyCloseIdx > -1 ? bodyCloseIdx : (htmlCloseIdx > -1 ? htmlCloseIdx : html.Length); sb.Append(html, innerHtmlStart, innerHtmlEnd - innerHtmlStart); fragmentEnd = GetByteCount(sb); sb.Append(EndFragment); if (innerHtmlEnd < html.Length) sb.Append(html, innerHtmlEnd, html.Length - innerHtmlEnd); if (htmlCloseIdx < 0) sb.Append("</html>"); } } else { // handle html with existing startend fragments just need to calculate the correct bytes offset (surround with html tag if missing) if (htmlOpenEndIdx < 0) sb.Append("<html>"); int start = GetByteCount(sb); sb.Append(html); fragmentStart = start + GetByteCount(sb, start, start + fragmentStartIdx) + StartFragment.Length; fragmentEnd = start + GetByteCount(sb, start, start + fragmentEndIdx); if (htmlCloseIdx < 0) sb.Append("</html>"); } // Back-patch offsets (scan only the header part for performance) sb.Replace("<<<<<<<<1", Header.Length.ToString("D9"), 0, Header.Length); sb.Replace("<<<<<<<<2", GetByteCount(sb).ToString("D9"), 0, Header.Length); sb.Replace("<<<<<<<<3", fragmentStart.ToString("D9"), 0, Header.Length); sb.Replace("<<<<<<<<4", fragmentEnd.ToString("D9"), 0, Header.Length); return sb.ToString(); } /// <summary> /// Calculates the number of bytes produced by encoding the string in the string builder in UTF-8 and not .NET default string encoding. /// </summary> /// <param name="sb">the string builder to count its string</param> /// <param name="start">optional: the start index to calculate from (default - start of string)</param> /// <param name="end">optional: the end index to calculate to (default - end of string)</param> /// <returns>the number of bytes required to encode the string in UTF-8</returns> private static int GetByteCount(StringBuilder sb, int start = 0, int end = -1) { int count = 0; end = end > -1 ? end : sb.Length; for (int i = start; i < end; i++) { _byteCount[0] = sb[i]; count += Encoding.UTF8.GetByteCount(_byteCount); } return count; } }