Linq Unable To Cast Issue

Question

When I try to run

InvTotal = g.Sum(d => d.Field<double>("Total")) < 0 ? "W" : "N", I get a

Unable to cast object of type 'System.Double' to type 'System.String' error.

How do I need to change the code for it it compile successfully.

Answer 1

I think you need correct parenthesis.

var InvTotal = (g.Sum(d => d.Field<double>("Total")) < 0) ? "W" : "N"

Without them the compiler will compile 0 ? "W" : "N" first, and the result of that will be used in the comparison.

Sometimes, the C# compiler needs a little help if it comes to the ? operator.

Answer 2

what is the type of InvTotal? I'm guessing it is currently a Double. Should work if you change the type to String, or remove the declaration of InvTotal and change your line to "var InvTotal = g.Sum..."