How to set HTML to clipboard in C#?

Solution 1:

When setting HTML text, you need to provide a header with additional information to what fragment of the html you actually want to paste while being able to provide additional styling around it:

Version:0.9
StartHTML:000125
EndHTML:000260
StartFragment:000209
EndFragment:000222
<HTML>
<head>
<title>HTML clipboard</title>
</head>
<body>
<!–StartFragment–><b>Hello!</b><!–EndFragment–>
</body>
</html>

With the header (and correct indexes), calling Clipboard.SetText with TextDataFormat.Html will do the trick.

To handle HTML and plain text pastes, you can’t use the Clipboard.SetText method, as it clears the clipboard each time it’s called; you need to create a DataObject instance, call its SetData method once with HTML and once with plain text, and then set the object to clipboard using Clipboard.SetDataObject.

Update

See "Setting HTML/Text to Clipboard revisited" for more details and ClipboardHelper implementation.

Solution 2:

I found some code: https://www.experts-exchange.com/questions/21966855/Create-a-hyperlink-in-VB-net-copy-to-clipboard-Should-be-able-to-paste-hyperlink-in-Microsoft-Word-Excel.html

This code handles the problems of updating the start and end indexes.

Converted to c#:

public void AddHyperlinkToClipboard(string link, string description)
{
    const string sContextStart = "<HTML><BODY><!--StartFragment -->";
    const string sContextEnd = "<!--EndFragment --></BODY></HTML>";
    const string m_sDescription = "Version:1.0" + Constants.vbCrLf + "StartHTML:aaaaaaaaaa" + Constants.vbCrLf + "EndHTML:bbbbbbbbbb" + Constants.vbCrLf + "StartFragment:cccccccccc" + Constants.vbCrLf + "EndFragment:dddddddddd" + Constants.vbCrLf;

    string sHtmlFragment = "<A HREF=" + Strings.Chr(34) + link + Strings.Chr(34) + ">" + description + "</A>";

    string sData = m_sDescription + sContextStart + sHtmlFragment + sContextEnd;
    sData = sData.Replace("aaaaaaaaaa", m_sDescription.Length.ToString().PadLeft(10, '0'));
    sData = sData.Replace("bbbbbbbbbb", sData.Length.ToString().PadLeft(10, '0'));
    sData = sData.Replace("cccccccccc", (m_sDescription + sContextStart).Length.ToString().PadLeft(10, '0'));
    sData = sData.Replace("dddddddddd", (m_sDescription + sContextStart + sHtmlFragment).Length.ToString().PadLeft(10, '0'));
    sData.Dump();
    Clipboard.SetDataObject(new DataObject(DataFormats.Html, sData), true );
}

Solution 3:

Let me share a helper for setting the clipboard data as HTML, which I've just come up with for my little side project #DevComrade:


var dataObject = new DataObject();
dataObject.SetData(DataFormats.Html, ClipboardFormats.ConvertHtmlToClipboardData(html);
Host.SetClipboardDataObject(dataObject);

internal static class ClipboardFormats
{
    static readonly string HEADER = 
        "Version:0.9\r\n" +
        "StartHTML:{0:0000000000}\r\n" +
        "EndHTML:{1:0000000000}\r\n" +
        "StartFragment:{2:0000000000}\r\n" +
        "EndFragment:{3:0000000000}\r\n";

    static readonly string HTML_START =
        "<html>\r\n" +
        "<body>\r\n" +
        "<!--StartFragment-->";

    static readonly string HTML_END =
        "<!--EndFragment-->\r\n" +
        "</body>\r\n" +
        "</html>";

    public static string ConvertHtmlToClipboardData(string html)
    {
        var encoding = new System.Text.UTF8Encoding(encoderShouldEmitUTF8Identifier: false);
        var data = Array.Empty<byte>();

        var header = encoding.GetBytes(String.Format(HEADER, 0, 1, 2, 3));
        data = data.Concat(header).ToArray();

        var startHtml = data.Length;
        data = data.Concat(encoding.GetBytes(HTML_START)).ToArray();

        var startFragment = data.Length;
        data = data.Concat(encoding.GetBytes(html)).ToArray();

        var endFragment = data.Length;
        data = data.Concat(encoding.GetBytes(HTML_END)).ToArray();

        var endHtml = data.Length;

        var newHeader = encoding.GetBytes(
            String.Format(HEADER, startHtml, endHtml, startFragment, endFragment));
        if (newHeader.Length != startHtml)
        {
            throw new InvalidOperationException(nameof(ConvertHtmlToClipboardData));
        }

        Array.Copy(newHeader, data, length: startHtml);
        return encoding.GetString(data);
    } 
}

I used this and this references. Also, kudos @DaveyBoy for spotting a bug.

Solution 4:

Arthur is right about the header, but the important thing to note here is that the data isn't going to be on the clipboard as plain text. You have to use CF_HTML. You can read about that at MSDN: http://msdn.microsoft.com/en-us/library/aa767917(v=vs.85).aspx To be proper, you'd have a CF_TEXT showing simply: "Hello!", and then CF_HTML with the HTML header and data, as in Arthur's example.

How to set HTML to clipboard in C#?

Solution 1:

Solution 2:

Solution 3:

Solution 4:

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