VS2015 Watch LINQ var错误：函数评估需要运行所有线程

Question

I have the simplest of LINQ queries; just testing out some database connections in my app:

public IHttpActionResult Get()
{
    var a = from c in Context.AspNetUsers where c.Id == 1 select c;
    return Ok();
}

When I break at the return and place a watch on 'a', then attempt to inspect the result, I get the error:

"The function evaluation requires all threads to run"

This only happens under VS2015 . If I run under VS2013, I am able to inspect the result as I would expect.

When I query for a single result as in:

    public IHttpActionResult Get()
    {
        var a = (from c in Context.AspNetUsers where c.Id == 1 select c).FirstOrDefault();
        return Ok();
    }

Then I don't get the error, regardless of VS version.

Is there an option setting somewhere that I have missed, or is this some known issue in VS2015?

Answer 1

"a" is essentially a query, or task - to invoke that query and get some data you need to call something that puts the data from that query in an object. So ToArray() or ToList() or something like that.