Function evaluation timed out when examining variables in debug/stepping through

Question

When debugging/stepping through code, and I try to examine a variable in the watch, I get errors for every inner-variable stating function evaluation timed out.

Does anyone know why this is and how to avoid it? As it impacts my ability to debug code.

This is within VS2010 Premium.

score 22 · Accepted Answer · answered Mar 15 '12 at 22:49

22

The most likely cause of this problem is an implicit evaluation of a property or ToString method which causes an issue with the CLR evaluation thread. To verify this turn off implicit evaluation.

Tools -> Options
Debugging
Uncheck "Enable property evaluation and other implicit function calls"

Then restart your scenario and see if it works.

answered Mar 15 '12 at 22:49

JaredPar

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this turned out to be a recursive call for me. On a property get() method, I was returning the public property instead of the private backing field. oops. – Induster May 01 '13 at 21:51
7

If I disable that option, I get "Implicit function evaluation is turned off by the user" error when inspecting an object in QuickWatch. – AlexVPerl Apr 16 '20 at 16:45
Same as AlexVPerl. – Brian Sep 23 '21 at 16:23
The same as guys above. This solution disables the evaluation, not solves the problem. – pawellipowczan Mar 18 '22 at 11:13

score 5 · Answer 2 · answered Mar 15 '12 at 22:55

Visual studio executes the property getter to get its value, if it takes a long time either because its doing something expensive you get this error. consider:

public class foo
{
    private object lockObject = new object();
    public int bar
    {
        get
        {
             lock(lockObject){
                return 42;
             }
         }
     }
     public int aMethod()
     {
         lock(lockObject)
         {
             var a = this.bar;
             return a*2;   //insert a break point here
          }
      }
}

If you add a break point on the return statement in aMethod the debugger will not be able to evaluate the bar property, because doing so requires that it acquires the lock object, but it won't be able to do so because the program will hold that lock forever while the break point is active

Function evaluation timed out when examining variables in debug/stepping through

2 Answers2

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