What does prefix to MoveNext mean in the stackstace?

Question

The .NET application crashes with the stack trace:

Call Stack:

Layouts!Layouts.Ribbon.SizeAndPositionControlViewModel+OnLayoutSelectionChanged>d__5.MoveNext() 
mscorlib_ni!System.Runtime.CompilerServices.AsyncMethodBuilderCore.<ThrowAsync>b__0(System.Object)
WindowsBase_ni!System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate, System.Object, Int32) 

The rest of the callstack is Windows code and does not matter.

Here's what the first call implies: In the async method OnLayoutSelectionChanged() in the instance of SizeAndPositionControlViewModel it failed in method MoveNext(). MoveNext() happens to be Microsoft code in a LINQ method method Any.

What does d__5 signify ?

Junko

Linq creates temporary IEnumerable classes that evaluate the results. d__5.MoveNext is an iteration over the IEnumerable it created. – Southwards

Answer 1

The d__5 portion is a prefix that is generated by the C# compiler to keep the construct unique from other generated members / types. In this case the d prefix means that it is an iterator or async method generated class (d is used for both). The number is just incremented for every name that is generated

Sestet

Answer 2

These are the names of lambda expressions which where auto-generated by the compiler (also anonymous methods may look similar when debugging).

Karyn

Answer 3

Several of the newer ways of creating returning IEnumerable objects are implemented in the compiler by defining and instantiating "anonymous" classes. The classes are actually required to have a name, so the compiler generates one like you are seeing. See e.g. this article for what is going on behind the scenes.

Baloney