C# array automatically gets set to null, why does this happen?

Asked Jan 05 '16 at 09:28

Active Jan 05 '16 at 09:46

Viewed 87 times

When I convert an List to array and don't use the array farther in my code it appears to be automatically going to null

like this:

String[] arr = list.ToArray();

now when I put a break point after it and hover over 'arr' it doesn't show a value but when i do it like this:

String[] arr = list.ToArray();
MessageBox.Show(arr[1].toString());

and then hover over 'arr' it shows the items.

why is it automatically set to null? could it be something in debug options of visualstudio or something to save memory space.

debugged as release when i type ?arr[1].ToString() in the Immediate Window it says it does not exist in the current context

edited Jan 05 '16 at 09:44

leppie

asked Jan 05 '16 at 09:28

Kolsters

5

Can't reproduce it this way, and most likely a misinterpretation of the debugging tools on your end. – Patrick Hofman Jan 05 '16 at 09:30
5

Are you debugging a DEBUG build or a RELEASE build? – Lasse V. Karlsen Jan 05 '16 at 09:31
Besides, the fact that hovering doesn't show something doesn't mean the variable has no value. It only means that hovering doesn't show something. It would be a different matter if you set a watch variable and found it to be null – Panagiotis Kanavos Jan 05 '16 at 09:32
You must be hovering when control of execution on first line only.i.e String[] arr = list.ToArray(); – Nitin Varpe Jan 05 '16 at 09:40
1

Windows doesn't handle your variables, the CLR does. – CodeCaster Jan 05 '16 at 09:42
Actually it loads the items when that array is accessed, thats why its shown null before the line : MessageBox.Show(arr[1].toString()); – Abhishek Anand Jan 05 '16 at 09:46
@Abhishek no, that is not how the compiler and CLR work. It doesn't "load" variables when required. A variable is either there, or optimized away. Not loaded on demand. – CodeCaster Jan 05 '16 at 09:47

0 Answers0