Hi

i think that is a issue with the variable scope.

in the if you have

if (...) {
   var node = ...
}
else {
   node = 
}

which mean the node variable is only setup in the first if statement - and doesn't exist outside of that if block.

so you need to move the delcleation out.

Personally I would do :

var node = Model.Content.GetPropertyValue<IEnumerable<IPublishedContent>>("linkPicker");
if (node == null || !node.Any()) {
   node = ... the decendants stuff.
}

but

if is worth noting you are returning two diffrent types of things from these statements as written in your code

Model.Content.Decendents.Where(...) will return a collection of nodes (so and IEnumerable

I didn't ask what type of picker linkPicker was (my bad) - but i assume its a MultiNodeTreePicker in which case you should change the GetPropertyValue<IPublishedContent> bit to GetPropertyValue<IEnumerable<IPublishedContent>>

You don't always need the <>

also check the IEnumerable bit - i am just typing this in the forums and oftem miss spell that !