How to reset digital signature of an InfoPath form during c# workflow in Sharepoint 2010?

Question

As the question says, I have an InfoPath form running on SP2010 using a c# workflow upon submission. If the form is rejected during workflow, then I need to reset it. I have everything under control, EXCEPT how to reset digital signatures to null, nill, nada, nothing, non-extant! Any ideas? I'm looking at Google now, but at current, I'm not even sure of an om for digital signatures?

Wow, i notice this question suddenly gaining alot of pop with bounty almost gone. Just putting it out there, I did not intend to not bounty someone, but i needed the answer earlier this week (2nd week Nov 2012) and thus i searched and played and teetered with code as much as possible till i ended up finding my own answer before anyone else answered me. However, for future reference, if someone gives a better answer, i'll gladly come back and rep them. Thank you all for the support and I really hope my answer is as useful to another as it was to me.

_NOW Bloggered ^&& Gisted _{May no one ever again have to search as hard as I did for this answer, :P}

Answer 1

¡¡¡   I   F O U N D   M Y F R I G G I N '   A N S W E R   ! ! !

_{¡¡¡ And it works from the workflow !!!}

Through much trial and tribulation I was finally able to come up with a solution. It involves a few steps. One, elevate security! Otherwise, non-admin users will cause the workflow to error. Seems like it should work this way, but ... Secondly, get the right schema! It took me a while to find mine, i forgot the exact steps, but, it's not hard to find. UPDATED: Can be found as an attribute of xmlDoc.Document, see updated code Step through (debug) your workflow, without the namespace/schema and highlight your document when it gets to it. One of the properties is an url that is the schema link. Anyway, you wanna see the solution!? Do ya? Look down!

SPSecurity.RunWithElevatedPrivileges(delegate()
{
    SPFile formFile = workflowProperties.Item.File;
    MemoryStream ms = new MemoryStream(formFile.OpenBinary());
    XmlTextReader rdr = new XmlTextReader(ms);
    XmlDocument xmlDoc = new XmlDocument();
    xmlDoc.Load(rdr);
    rdr.Close();
    ms.Close();
    XmlNamespaceManager nsm = new XmlNamespaceManager(xmlDoc.NameTable);
    String schemaUri = xmlDoc.DocumentElement.GetAttributeNode("xmlns:my") != null ? xmlDoc.DocumentElement.GetAttributeNode("xmlns:my").Value : "http://schemas.microsoft.com/office/infopath/2003/myXSD/2012-09-04T20:19:31";
    nsm.AddNamespace("my", schemaUri);
    XmlNode nodeSignatureCollection = xmlDoc.DocumentElement.SelectSingleNode("my:signatures1", nsm);
    if (nodeSignatureCollection != null)
    {
        if (nodeSignatureCollection.HasChildNodes)
        {
            foreach (XmlNode nodeSignature in nodeSignatureCollection.ChildNodes)
            {
                //  HERE IT IS!!!
                if (nodeSignature.HasChildNodes && !nodeSignature.IsReadOnly) nodeSignature.RemoveAll();
            }
        }
    }
    byte[] xmlData = System.Text.Encoding.UTF8.GetBytes(xmlDoc.OuterXml);
    formFile.SaveBinary(xmlData);
    formFile.Update();
});

Keep in mind, this setup is for going through multiple signatures. Although I doubt anything would change if there was only one signature.

Any suggestions on making this sweeter and smaller are accepted, however, I must request an explanation. Honestly, I barely understand what is going on here!