Q:

How do I store an XML value in my .NET App. Config file

I am trying to store an xml value in my app.config file.  
The app.config does not like this and I cannot use the <![ CDATA[ construct to ignore the XML'ness of my value. 
Is there a way to do it? 
Value example:<FieldRef Name='LinkfileName' Nullable='True'/><FieldRef Name='Web' Nullable='True'/>

A:

You can save an XML document as text in an attribute value if you escape the character entities:
&lt;FieldRef Name=&quot;Linkfilename&quot; ...

You can then use XmlDocument. Load() to parse the text value. 
Note that this won't work for your example because your value is an XML document fragment and not a well-formed XML document.   You either need to wrap it in an enclosing document element (whose markup will still be escaped) or use a properly-initialized XmlReader to process the value once you've retrieved it from the configuration.