Why does Select return a boolean?

Question

I'm working with Entity Framework 6 in MVC 5. I have the following method: ``` [HttpPost] public ActionResult UpdateDetails(ApplicationUser applicationUser) { var context = new ApplicationDbContext(); var user = context.Users.Select(x => x.UserName == applicationUser.UserName).FirstOrDefault(); //etc etc } ``` Users is an `IDbSet<ApplicationUser>`. Why am I getting a bool back from the Select method? My expectation would be to get an `ApplicationUser` object back. Why isn't this the case? Thanks

Accepted Answer

`Select()` projects an element of a sequence. Since `x.UserName == applicationUser.UserName` returns a `bool`, the result of the method will be a boolean.

What you want requires the `Where` method. This filters the sequence based on the specified predicate:

```
var user = context.Users.Where(x => x.UserName == applicationUser.UserName).FirstOrDefault();
```

Which can be shortened to:

```
var user = context.Users.FirstOrDefault(x => x.UserName == applicationUser.UserName);
```

This is possible, since this overload of `FirstOrDefault()` takes a filter predicate as second parameter.

Why does Select return a boolean?

Solution

Problem