How to inspect the return value of a function in Visual Studio while debugging without creating a temporary variable
I have a lot of methods that are just 1 expression, e.g.
internal IEnumerable<Employee> CurrentEmployees()
=> _employees.Where
(e => !e.HasBeenFired &&
e.StartDate >= DateTime.Today &&
!e.OnExtendedLeave);
If i want to inspect the result of that function, in the debugger, it's a bit of a pain.
In the past I've sometimes refacted the method to be two lines -- with a returnValue variable... just so it's easier to inspect.
internal IEnumerable<Employee> CurrentEmployees()
{
var returnValue =
_employees.Where
(e => !e.HasBeenFired &&
e.StartDate >= DateTime.Today &&
!e.OnExtendedLeave);
return returnValue; // SET breakpoint here to inspect returnValue
}
Turns out there is $ReturnValue automatic variable, that the debugger creates-- in some versions of Visual Studio after 2013. Or it might be $ReturnValue1, or $returnvalue, in different versions of visual studio.
Marc Gravell covers it here, and states:
The value can only be seen directly after returning from the function, thus the easiest way to access it is by putting a breakpoint on the function call and step over (F10) the call.
If it's available, you will see it listed in the "autos" window. (Available from the debugging windows menu.)