Store arbitrary application data in System.Windows.Forms.RichTextBox

Question

Hello,

Does anyone know of a way to store arbitrary data in a RichTextBox without the user being able to see this data? The 2007 RTF specification includes annotations ("\atnid", "\atnauthor", "\annotation", etc.) but whenever I insert these into a RichTextBox's .Rtf, the annotations disappear (presumably because the RichTextBox doesn't support RTF annotations.) I have a related question about whether it is possible to store the information inside a Metafile image. Either of these solutions would be acceptable. TIA.

What I'm trying is something like this:

string objectXml = MySerialization.ToXml(object);
string commentRtfFragment = String.Format(@"{{\*\atnid MyApp}}{{\*\atnauthor MyApp}}{{\*\annotation {0}}}", objectXml);

string imageRtf = String.Format(@"{{\rtf1 {{\pict\wmetafile{0}\picw{1}\pich{2}\picwgoal{3}\pichgoal{4} {5}}}{6}}}",
    PixelMappingMode.MM_ANISOTROPIC, picw, pich, picwgoal, pichgoal, imageHex, commentRtfFragment);
richTextBox.SelectedRtf = imageRtf;

Update: The application metadata ("annotations") must correspond with particular locations in the RTF. There will also be multiple annotations per RichTextBox (or RTF document if you like.) I also want the metadata to persist with the RTF. So while it would be possible to persist the metadata in a control.Tag, then I would have to take care of adding the information to the database myself, noting whenever the user edited the RTF and somehow determine the new location of the metadata after the edit.

Answer 1

I don't know if there's any special way for doing this for RTF documents, but if you just want to store some data in a control (any kind of Control) without showing it to the user, you could use the Tag property as can be seen here: Control.Tag

Answer 2

I think ho1 has the right idea. Control.Tag is an object so you could use a generic data structure like List, Hash, Dictionary, etc. to store your multiple annotations and store that in the Tag property.

Answer 3

The richtext control supports hidden words with \v and turns hidden off with \v0 and no, I have not confused them even though logically \v would stand for visible it does the opposite.