Regarding SPFieldMultiLineText (Add HTML/URL content to a field) programmatically

I recently tried so set some HTML content in a SharePoint list column of type SPFieldMultiLineText.

My first approach was this piece of code:

SPFieldMultiLineText field = item.Fields.GetFieldByInternalName("Associated Documents") as SPFieldMultiLineText;

StringBuilder docList = new StringBuilder();
docList.Append("
");
foreach (DataRow docRow in addDocs)
{
DataRow[] parent = dr.Table.DataSet.Tables[0].Select("DOK_ID=" + docRow["DOK_MGD_ID"].ToString());
if (parent != null && parent.Length > 0)
{
docList.AppendFormat("{1}", parent[0]["FilePath"].ToString(), parent[0]["Title"].ToString());
}
}
if (docList.Length > 0)
{
// remove trailing tag
docList.Remove(docList.Length-5, 5);
}
docList.Append("
");
string newValue = docList.ToString();
item[field.Title] = newValue;

What this code does is to get all associated documents to the main document and to add these document uri links to the "Associated Documents" column in my custom SharePoint list.

I intended to render the following content in the enhanced rich text field (which works if I enter the content through the SharePoint GUI in the edit form):

<div>
<a target='_blank' href='\\publicshare\docs$\Test1.pdf'>Test 1</a><br/>
<a target='_blank' href='\\publicshare\docs$\Test2.pdf'>Test 2</a><br/>
<a target='_blank' href='\\publicshare\docs$\Test3.pdf'>Test 3</a><br/>
<a target='_blank' href='\\publicshare\docs$\Test4.pdf'>Test 4</a>
</div>

Doing the same via SP object model it will result in the following nasty result:

<div>
<a target=_blank >Test 1</a><br/>
<a target=_blank >Test 2</a><br/>
<a target=_blank >Test 3</a><br/>
<a target=_blank >Test 4</a>
</div>

It drove me nuts because I tried several HTML encode methods or different formatting and nothing helped.
Then after a couple of days and some more gray hairs I got a brilliant idea what could break the A href links of my html source.

I want to point out and talk about the following line:
docList.AppendFormat("{1}
", parent[0]["FilePath"].ToString(), parent[0]["Title"].ToString());

Using UNC paths in the href attribute of the "A" tag usually is not a problem.

For example you have the following a href tag:
<a target='_blank' href='\\share\test.doc'>test doc</a>
the browser will render the href url as:
file://share/test.doc
this behavior also works with a standard SharePoint hyperlink field, except in this scenario

To make this whole thing work you must explicitely convert the UNC path to a valid URI path.

The following line shows the result which solved this whole issue:
docList.AppendFormat("{1}
", new Uri(parent[0]["FilePath"].ToString()).AbsoluteUri, parent[0]["Title"].ToString());