Visual Studio during Debugging: The function evaluation requires all threads to run

Question

I'm suddenly getting a strange error while debugging. Up to now the variable in the watch windows has been showing correctly. Now I am always getting this error message in the watch windows:

The function evaluation requires all threads to run

I am not able to check any variable anymore. I am not explicitly working with threads. What can I do to get it working again?

I already disabled, as mentioned in some forums, the function: "Enable property Evaluation and other implicit function Calls" in the option window of the debugger. But without success, and it gives me this error:

Error Implicit Function evaluation disabled by the user

Answer 1

From the msdn forum:

This isn't an error in and of itself, but more of a feature of your debugger. Some properties require code to be executed in order for the property to be read, but if this requires cross-thread interaction, then other threads may have to run as well. The debugger doesn't do this automatically, but certainly can, with your permission. Just click the little evaluate icon and it will run your code and evaluate the property.

For further details on this behaviour check this excelent article

Answer 2

I ran into this issue when just trying to get items from a table called "AGENCY" using Entity Framework:

var agencies = db.AGENCY.OrderBy(e => e.FULLNAME);

Hovering over agencies in debug mode, clicking to expand the options, and clicking Results would give the dreaded "The function evaluation requires all threads to run" with a "Do Not Enter" icon at the end that, on which, clicking did nothing.

2 possible solutions:

1. Add .ToList() at the end:

   var agencies = db.AGENCY_TABLE.OrderBy(e => e.FULLNAME).ToList();

   List<AGENCY_TABLE> agencies = db.AGENCY_TABLE.OrderBy(e => e.FULLNAME).ToList();

   Credit goes to Hp93 for helping me come to this solution. In the comments on MUG4N's answer where I found this solution, it also mentions trying .Any() instead of .ToList(), but this gives a Boolean instead of a <T>, like <AGENCY> is, so it probably wouldn't help.

2. Workaround - try a different path in the debug options. I found that I could click on the "Non-Public Members" > "_internalQuery" > ObjectQuery > Results View and get my values that way.