From what I am reading here if you instantiate something inside a using statement than it should catch any exceptions and skip the code block. I am still seeing unhandled exceptions happen for file not found with this:
using (TextReader sv = File.OpenText(@"sv\.sv"))
{
char[] k = { ':' };
lastWsp = sv.ReadLine().Split(k)[1];
}
Am I misunderstanding the MSDN article or do I need to set a switch in the compiler?
using translates into try-finally block, it doesn't have catch, so you are misunderstanding the article. It will not catch any exception, It will only make sure to dispose the object in case of an exception.
In your case since it a FileNotFound exception, your object will not be initialized.
Your code would translate into something like:
{
TextReader sv = null;
try
{
sv = File.OpenText(@"sv\.sv");
char[] k = { ':' };
lastWsp = sv.ReadLine().Split(k)[1];
}
finally
{
if(sv != null)
sv.Dispose();
}
}
In the above code in case of exception, it will try to dispose your object sv. But the exception will remain unhandled .
Since in your code, the exception is FileNotFound your object sv will remain null (uninitialized) and hence there will be no reason to call Dispose. But imagine if you have valid file path, and you get an exception at sv.ReadLine().Split(k)[1]; then it will dispose your TextReader sv, and that exception will propagate up in the hierarchy because there is no catch block.
Yes, you are misunderstanding the article.
using declares that the resource will be closed with Dispose regardless of any exceptions thrown within the block. It will not catch the exceptions for you.
MSDN article is saying that even if exception is thrown from within the using block you have a guarantee that .Dispose() will be called on, in your case, object sv. Thats all it says and in addition to that, you are given the instructions on how to achieve that using try and finally:
You can achieve the same result by putting the object inside a try block and then calling Dispose in a finally block
So it seems you misinterpreted the article.
usingstatement doesn't handle exceptions. If an exception occurs inside the body of the using, then the TextReader is guaranteed to be Disposed, but the exception will still not be handled.