C# 7.0 Value Tuple compile error?

Question

When I am trying to compile the following code:

var post = iPostService.GetAll().Select(x => (x.Title, x.Author));

I get the compiler error: 'An expression tree may not contain a tuple literal.'

So I also tried this:

var post = iPostService.GetAll().
                    Select(x => new ValueTuple<string, string>(x.Title, x.Author))

The result is runtime error:'Cannot resolve method Void .ctor(System.String, System.String) because the declaring type of the method handle System.ValueTuple`2[T1,T2] is generic. Explicitly provide the declaring type to GetMethodFromHandle.'

I googled to find out the solution to this problem but nothing really helpful.

Any help really appreciated.

Thanks

Answer 1

It works for me, create a tuple first and convert it to a ValueTuple：

var post = iPostService.GetAll().
           Select(x => new Tuple<string, string>(x.Title, x.Author).ToValueTuple())