How to handle HtmlDocument null exception

Question

I am checking a HtmlDocument() by html id called shippingMessage_ftinfo_olp_1 but problem is that i am unable to check if this is a null exception. Because when i set if !=null still it throws exception. Anyone can tell me how can i check it if its null without this exception?

System.NullReferenceException: 'Object reference not set to an instance of an object.'

HtmlDocument htmlDoc = new HtmlDocument();
htmlDoc.LoadHtml(response);
string gerLang = "";
if (htmlDoc.GetElementbyId("shippingMessage_ftinfo_olp_1").InnerText != null)
{
    gerLang = htmlDoc.GetElementbyId("shippingMessage_ftinfo_olp_1").InnerText;
    if(gerLang.Contains("AmazonGlobal Express-Zustellung"))
    {
        _outOfStock = false;
    }
}

Possible duplicate of [What is a NullReferenceException, and how do I fix it?](https://stackoverflow.com/questions/4660142/what-is-a-nullreferenceexception-and-how-do-i-fix-it) — Kirk Larkin, Sep 15 '18 at 10:56
Someone will be along soon to close this out as a duplicate of the question I've linked. However, you want to check that `htmlDoc.GetElementbyId("shippingMessage_ftinfo_olp_1") != null` before you check the `InnerText`. — Kirk Larkin, Sep 15 '18 at 10:59
When someone dont know the solution, its a way to mark as duplicate with a source manual book! Good job but the great guy not hesitate to answer as i selected bellow — john Cogdle, Sep 15 '18 at 11:14
I also voted your question as a duplicate of that question, but provided an answer as a community wiki answer to help you solve your exact problem :-) (not to say that Kirk didn't also provide a solution above). — ProgrammingLlama, Sep 15 '18 at 11:15
Real solution is so quick just put `?` anywhere you dont trust! haha thanks to mark as duplicate also! — john Cogdle, Sep 15 '18 at 11:16

score 1 · Accepted Answer · answered Sep 15 '18 at 10:59

1

Use a null conditional operator:

if (htmlDoc.GetElementbyId("shippingMessage_ftinfo_olp_1")?.InnerText != null)

If htmlDoc can be null, also change that to htmlDoc?.GetEle....

Reasoning: A null conditional operator short-circuits the evaluation if the object being evaluated is null, preventing you from getting an exception, in favour of evaluating to null.

answered Sep 15 '18 at 10:59

ProgrammingLlama

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I learned new one from you! great answer man! Thanks. Works like charm – john Cogdle Sep 15 '18 at 11:08

How to handle HtmlDocument null exception

1 Answers1