Question

If you have a simple Linq query like:

var result = from record in db.Customer
             select new { Text = record.Name,
                          Value = record.ID.ToString() };

which is returning an object that can be mapped to a Drop Down List, is it possible to dynamically specify which fields map to Text and Value?

Of course, you could do a big case (switch) statement, then code each Linq query separately but this isn’t very elegant. What would be nice would be something like:

(pseudo code)

var myTextField = db.Customer["Name"];  // Could be an enumeration??
var myValueField = db.Customer["ID"];   // Idea: choose the field outside the query

var result = from record in db.Customer
             select new { Text = myTextField,
                          Value = myValueField };

Answer 1

Right way to do this is with closures.

Func<Customer, string> myTextField = (Customer c) => c["Name"];
Func<Customer, int> myValueField = (Customer c) => c["ID"];

var result = from record in db.Customer
             select new { Text = myTextField(record),
                          Value = myValueField(record) };

The one limitation is that your definition of myTextField always needs to return a string.