The ':' character, hexadecimal value 0x3A, cannot be included in a name
If you want to use namespaces, LINQ to XML makes that really easy:
XNamespace ab = "http://whatever-the-url-is";XElement tempElement = doc.Descendants(ab + "test").FirstOrDefault();Look for an xmlns:ab=... section in your document to find out which namespace URI "ab" refers to.
Try putting your namespace in { ... } like so:
string xfaNamespace = "{http://www.xfa.org/schema/xfa-template/2.6/}";
I was having the same error. I found I was adding code...
var ab = "http://whatever-the-url-is";... but ab was determined to be a string. This caused the error reported by OP. Instead of using the VAR keyword, I used the actual data type XNamespace...
XNamespace ab = "http://whatever-the-url-is";... and the problem went away.