Storing Equal Signs (=) in XML Documents

Question

I'm facing a problem that Google couldn't solve yet!

I'm trying to store URLs in an XML file. Problem is that these URLs contain Equal Signs (=) in them. And that generates an error.

Here is my code: (**token is a variable that contains the URL)

Dim child As String = vbCrLf & "<Link URL='" & token & "'></Link>"
Dim fragment As XmlDocumentFragment = doc.CreateDocumentFragment
fragment.InnerXml = child

The error message: (Error line and position are meaningless here)

'=' is an unexpected token. The expected token is ';'. Line 2, position 133.

I've replaced all '&' symbols with '&amp' in case they were the ones causing the error, but no luck so far.

Answer 1

You should never use string manipulation to create XML. If you use the XML APIs of .NET, they will take care of all the special characters for you. Try:

XmlElement linkElement = doc.CreateElement("Link");
XmlAttribute urlAttribute = doc.CreateAttribute("URL");
urlAttribute.Value = token;
linkElement.SetAttributeNode(urlAttribute);
fragment.AppendChild(linkElement);

Answer 2

Try adding this line below the first line:

-- insert this line; should make the "=" sign safe for XML...
token = System.Web.HttpUtility.UrlEncode(token)

Dim child As String = vbCrLf & "<Link URL='" & token & "'></Link>"
Dim fragment As XmlDocumentFragment = doc.CreateDocumentFragment
fragment.InnerXml = child

Answer 3

You should not replace & with &amp, you should replace them with &.

Or better yet, create a node in your fragment and add an attribute to it. That way the object will encode the data correctly for you.

Dim fragment As XmlDocumentFragment = doc.CreateDocumentFragment()
Dim node As XmlElement = doc.CreateElement("Link")
Dim attr as XmlAttribute = doc.CreateAttribute("URL")
attr.Value = token
node.Attributes.Append(attr)
fragment.AppendNode(node)