Variable is null, but right hand is not null
While debugging I noticed something weird:
the result var is shown as null, both in mouse hover and in the watch, but the right hand side is actually returning non-null value as you can see in the watch.
Any ideas why?
EDIT: the result variable is also declared in the IF statement, something like this:
if (somethingIsTrue) { var result = xxx; }
else { var result = yyy; }
As soon as I renamed the second result to something else, all started showing correctly.
c# visual-studio debugging visual-studio-2017
edited Nov 20 '18 at 6:34
Jon Skeet
1088k68979408439
asked Nov 20 '18 at 3:35
Veselin VasilevVeselin Vasilev
2,36411015
|
show 1 more comment
While debugging I noticed something weird:
the result var is shown as null, both in mouse hover and in the watch, but the right hand side is actually returning non-null value as you can see in the watch.
Any ideas why?
EDIT: the result variable is also declared in the IF statement, something like this:
if (somethingIsTrue) { var result = xxx; }
else { var result = yyy; }
As soon as I renamed the second result to something else, all started showing correctly.
c# visual-studio debugging visual-studio-2017
edited Nov 20 '18 at 6:34
Jon Skeet
1088k68979408439
asked Nov 20 '18 at 3:35
Veselin VasilevVeselin Vasilev
2,36411015
Clean and rebuild?
– Michael Randall
Nov 20 '18 at 3:37
1
Maybe a case of multiple evaluation? First call gets null, puts it in result. Second call (to display it in the Watch) gets a value. What doesGetCachedData()do?
– Ian Mercer
Nov 20 '18 at 3:42
actually in the main if block the result variable is also defined, so probably that's what's causing it. if (something) { var result = xxx; } else { var result = yyy; } as soon as I renamed it to something else in the Else block - all is shown properly.
– Veselin Vasilev
Nov 20 '18 at 3:49
1
Meh. You are probably just running up against deferred execution. blogs.msdn.microsoft.com/charlie/2007/12/10/…
– P.Brian.Mackey
Nov 20 '18 at 3:50
@pbrian Not convinced the issue here could be deferred execution. Look at the watch, the right hand expression does return an object instance, not some IQueryable or something. It seems more like what mercer mentioned.
– Sнаđошƒаӽ
Nov 20 '18 at 4:11
|
show 1 more comment
While debugging I noticed something weird:
the result var is shown as null, both in mouse hover and in the watch, but the right hand side is actually returning non-null value as you can see in the watch.
Any ideas why?
EDIT: the result variable is also declared in the IF statement, something like this:
if (somethingIsTrue) { var result = xxx; }
else { var result = yyy; }
As soon as I renamed the second result to something else, all started showing correctly.
c# visual-studio debugging visual-studio-2017
edited Nov 20 '18 at 6:34
Jon Skeet
1088k68979408439
asked Nov 20 '18 at 3:35
Veselin VasilevVeselin Vasilev
2,36411015
While debugging I noticed something weird:
the result var is shown as null, both in mouse hover and in the watch, but the right hand side is actually returning non-null value as you can see in the watch.
Any ideas why?
EDIT: the result variable is also declared in the IF statement, something like this:
if (somethingIsTrue) { var result = xxx; }
else { var result = yyy; }
As soon as I renamed the second result to something else, all started showing correctly.
c# visual-studio debugging visual-studio-2017
c# visual-studio debugging visual-studio-2017
edited Nov 20 '18 at 6:34
Jon Skeet
1088k68979408439
asked Nov 20 '18 at 3:35
Veselin VasilevVeselin Vasilev
2,36411015
edited Nov 20 '18 at 6:34
Jon Skeet
1088k68979408439
asked Nov 20 '18 at 3:35
Veselin VasilevVeselin Vasilev
2,36411015
edited Nov 20 '18 at 6:34
Jon Skeet
1088k68979408439
edited Nov 20 '18 at 6:34
Jon Skeet
1088k68979408439
edited Nov 20 '18 at 6:34
Jon Skeet
1088k68979408439
1088k68979408439
asked Nov 20 '18 at 3:35
Veselin VasilevVeselin Vasilev
2,36411015
asked Nov 20 '18 at 3:35
Veselin VasilevVeselin Vasilev
2,36411015
asked Nov 20 '18 at 3:35
Veselin VasilevVeselin Vasilev
2,36411015
2,36411015
Clean and rebuild?
– Michael Randall
Nov 20 '18 at 3:37
1
Maybe a case of multiple evaluation? First call gets null, puts it in result. Second call (to display it in the Watch) gets a value. What doesGetCachedData()do?
– Ian Mercer
Nov 20 '18 at 3:42
actually in the main if block the result variable is also defined, so probably that's what's causing it. if (something) { var result = xxx; } else { var result = yyy; } as soon as I renamed it to something else in the Else block - all is shown properly.
– Veselin Vasilev
Nov 20 '18 at 3:49
1
Meh. You are probably just running up against deferred execution. blogs.msdn.microsoft.com/charlie/2007/12/10/…
– P.Brian.Mackey
Nov 20 '18 at 3:50
@pbrian Not convinced the issue here could be deferred execution. Look at the watch, the right hand expression does return an object instance, not some IQueryable or something. It seems more like what mercer mentioned.
– Sнаđошƒаӽ
Nov 20 '18 at 4:11
|
show 1 more comment
Clean and rebuild?
– Michael Randall
Nov 20 '18 at 3:37
1
Maybe a case of multiple evaluation? First call gets null, puts it in result. Second call (to display it in the Watch) gets a value. What doesGetCachedData()do?
– Ian Mercer
Nov 20 '18 at 3:42
actually in the main if block the result variable is also defined, so probably that's what's causing it. if (something) { var result = xxx; } else { var result = yyy; } as soon as I renamed it to something else in the Else block - all is shown properly.
– Veselin Vasilev
Nov 20 '18 at 3:49
1
Meh. You are probably just running up against deferred execution. blogs.msdn.microsoft.com/charlie/2007/12/10/…
– P.Brian.Mackey
Nov 20 '18 at 3:50
@pbrian Not convinced the issue here could be deferred execution. Look at the watch, the right hand expression does return an object instance, not some IQueryable or something. It seems more like what mercer mentioned.
– Sнаđошƒаӽ
Nov 20 '18 at 4:11
Clean and rebuild?
– Michael Randall
Nov 20 '18 at 3:37
Clean and rebuild?
– Michael Randall
Nov 20 '18 at 3:37
1
1
Maybe a case of multiple evaluation? First call gets null, puts it in result. Second call (to display it in the Watch) gets a value. What does
GetCachedData() do?– Ian Mercer
Nov 20 '18 at 3:42
Maybe a case of multiple evaluation? First call gets null, puts it in result. Second call (to display it in the Watch) gets a value. What does
GetCachedData() do?– Ian Mercer
Nov 20 '18 at 3:42
actually in the main if block the result variable is also defined, so probably that's what's causing it. if (something) { var result = xxx; } else { var result = yyy; } as soon as I renamed it to something else in the Else block - all is shown properly.
– Veselin Vasilev
Nov 20 '18 at 3:49
actually in the main if block the result variable is also defined, so probably that's what's causing it. if (something) { var result = xxx; } else { var result = yyy; } as soon as I renamed it to something else in the Else block - all is shown properly.
– Veselin Vasilev
Nov 20 '18 at 3:49
1
1
Meh. You are probably just running up against deferred execution. blogs.msdn.microsoft.com/charlie/2007/12/10/…
– P.Brian.Mackey
Nov 20 '18 at 3:50
Meh. You are probably just running up against deferred execution. blogs.msdn.microsoft.com/charlie/2007/12/10/…
– P.Brian.Mackey
Nov 20 '18 at 3:50
@pbrian Not convinced the issue here could be deferred execution. Look at the watch, the right hand expression does return an object instance, not some IQueryable or something. It seems more like what mercer mentioned.
– Sнаđошƒаӽ
Nov 20 '18 at 4:11
@pbrian Not convinced the issue here could be deferred execution. Look at the watch, the right hand expression does return an object instance, not some IQueryable or something. It seems more like what mercer mentioned.
– Sнаđошƒаӽ
Nov 20 '18 at 4:11
|
show 1 more comment
1 Answer
1
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When your code is like this
if (somethingIsTrue) { var result = xxx; } else { var result = yyy; }
Then that 'result' variable is (re)declared within the scope of that if-statement. That means the value is only available within that block.
Solution: declare the variable outside of the block (if you haven't done that already) and remove the 'var's inside the 'if' and 'else' blocks
answered Nov 20 '18 at 6:31
Hans KestingHans Kesting
29.3k55893
add a comment |
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When your code is like this
if (somethingIsTrue) { var result = xxx; } else { var result = yyy; }
Then that 'result' variable is (re)declared within the scope of that if-statement. That means the value is only available within that block.
Solution: declare the variable outside of the block (if you haven't done that already) and remove the 'var's inside the 'if' and 'else' blocks
answered Nov 20 '18 at 6:31
Hans KestingHans Kesting
29.3k55893
add a comment |
When your code is like this
if (somethingIsTrue) { var result = xxx; } else { var result = yyy; }
Then that 'result' variable is (re)declared within the scope of that if-statement. That means the value is only available within that block.
Solution: declare the variable outside of the block (if you haven't done that already) and remove the 'var's inside the 'if' and 'else' blocks
answered Nov 20 '18 at 6:31
Hans KestingHans Kesting
29.3k55893
add a comment |
When your code is like this
if (somethingIsTrue) { var result = xxx; } else { var result = yyy; }
Then that 'result' variable is (re)declared within the scope of that if-statement. That means the value is only available within that block.
Solution: declare the variable outside of the block (if you haven't done that already) and remove the 'var's inside the 'if' and 'else' blocks
answered Nov 20 '18 at 6:31
Hans KestingHans Kesting
29.3k55893
When your code is like this
if (somethingIsTrue) { var result = xxx; } else { var result = yyy; }
Then that 'result' variable is (re)declared within the scope of that if-statement. That means the value is only available within that block.
Solution: declare the variable outside of the block (if you haven't done that already) and remove the 'var's inside the 'if' and 'else' blocks
answered Nov 20 '18 at 6:31
Hans KestingHans Kesting
29.3k55893
answered Nov 20 '18 at 6:31
Hans KestingHans Kesting
29.3k55893
answered Nov 20 '18 at 6:31
Hans KestingHans Kesting
29.3k55893
answered Nov 20 '18 at 6:31
Hans KestingHans Kesting
29.3k55893
29.3k55893
add a comment |
add a comment |
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Clean and rebuild?
– Michael Randall
Nov 20 '18 at 3:37
1
Maybe a case of multiple evaluation? First call gets null, puts it in result. Second call (to display it in the Watch) gets a value. What does
GetCachedData()do?– Ian Mercer
Nov 20 '18 at 3:42
actually in the main if block the result variable is also defined, so probably that's what's causing it. if (something) { var result = xxx; } else { var result = yyy; } as soon as I renamed it to something else in the Else block - all is shown properly.
– Veselin Vasilev
Nov 20 '18 at 3:49
1
Meh. You are probably just running up against deferred execution. blogs.msdn.microsoft.com/charlie/2007/12/10/…
– P.Brian.Mackey
Nov 20 '18 at 3:50
@pbrian Not convinced the issue here could be deferred execution. Look at the watch, the right hand expression does return an object instance, not some IQueryable or something. It seems more like what mercer mentioned.
– Sнаđошƒаӽ
Nov 20 '18 at 4:11