In C# Object Instantiation, is a Null Check Needed if Catching Exceptions

Question

I have been looking on stackoverflow, but do not see the ansswer yet. Note: that I did see some good responses in C++, but not C#.

Is there any benefit in checking for null if (reader == null) as below, or will issues causing it to be null already cause an exception making if (reader == null) unreachable (with reader == null being true)?

try
{
    var reader = new PhotoReader();
    if (reader == null)
    {
        throw new InvalidOperationException("PhotoReader could not be created.");
    }
}
catch (Exception ex)
{
    // let user know failed object creation, etc.
    <...>
}

CodeCaster regarding duplicate: That is great. I just did not see it from my search criteria. Please point me to the duplicate and I will check it out. Thank you. — Buck, May 24 '14 at 19:31
CodeCaster: Just let me know if I should delete this even though it has answers. Difference in title may cause this to come up in searches versus the other. Thanks! — Buck, May 25 '14 at 11:21

score 5 · Accepted Answer · answered May 24 '14 at 19:08

5

No, there is no way you get null as result of contructor call in c#.

Constructor may throw an exception itself, but it will break your execution flow anyway.

answered May 24 '14 at 19:08

MarcinJuraszek

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score 1 · Answer 2 · answered May 24 '14 at 19:09

1

The fact that you instantiate reader by assigning the result of a class's constructor means that it will never be null, so that check is unnecessary.

answered May 24 '14 at 19:09

adv12

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In C# Object Instantiation, is a Null Check Needed if Catching Exceptions

2 Answers2