CODEWITHSUNDEEP
visual-studio
Álvaro García
Álvaro García

Reputation: 19396

Why can't the breakpoint evaluate the expression?

I have this code:

foreach(MyType iterator in myList)
{
    Object myObject = iterator.MyProperty;
}

Well, really this is not my code, is an example, what I want to do is set a breakpoint into the foreach and check if the iterator.MyProperty is null.

In the condition of my breakpoint I set:

iterator.MyProperty == null

But I get an error because the breakpoint can't evaluate the condition.

I am using VS2015 community.

Thank you so much.

Upvotes: 2

Views: 185

Answers (2)

CiaPan
CiaPan

Reputation: 9570

Your debugger can read and test values of variables. However it can't execute your code.

If MyProperty was a simple variable in the iterator object it certainly would be properly handled by a debugger's breakpoint condition expression. But it is probably a property with some getter function, so the debugger would have to jump into your code in a breakpoint handler to obtain the desired value — and it simply is not allowed to do that.

Upvotes: 3

Rahul Tripathi
Rahul Tripathi

Reputation: 172578

You can try like this:

using System.Diagnostics;
........

foreach(MyType iterator in myList)
{
    if (iterator.MyProperty == null) 
    {
       Debugger.Break();
    }
    Object myObject = iterator.MyProperty;
}

You may also refer: http://weblog.west-wind.com/posts/2013/Nov/21/Visual-Studio-2013-Could-not-evaluate-Expression-Debugger-Abnormality

Upvotes: 2

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