CODEWITHSUNDEEP
c#xmlxml-parsing
Eric
Eric

Reputation: 1268

NullException XML Parsing

I'm having a problem with parsing XML in C#, my XML file looks like this:

<xml>
    <category>books</category>
    <id>1</id>
    <title>lemony</title>
    <sub>
        <title>lemonyauthor</title>
    </sub>
</xml>
<xml>
    <category>comics</category>
    <id>2</id>
    <sub>
        <title>okauthor</title>
    </sub>
</xml>

As you can see sometimes the title in "XML" is returned, sometimes not.

My code in C# to parse this looks like:

string _Title;

foreach (XElement str in xmlDoc.Descendants("xml"))
{
    _Title = "";

        if (str.Element("title").Value != null)
            _Title = str.Element("title").Value;

        foreach (XElement cha in str.Descendants("sub"))
        {
            if (_Title.Length < 1 && cha.Element("Title").Value != null)
                    _Title = cha.Element("title").Value;
        }
}

How do I keep the line if (str.Element("category").Value != null) from returning a NullException?

Is using try & catch the only way?

Upvotes: 0

Views: 76

Answers (2)

BartoszKP
BartoszKP

Reputation: 35901

Change this:

if (str.Element("title").Value != null)
    _Title = str.Element("title").Value;

to this:

var titleElement = str.Element("title");
if (titleElement != null)
    _Title = titleElement.Value;

Upvotes: 2

ChrisF
ChrisF

Reputation: 137148

If you are expecting str.Element("title") (which is the most likely cause of of the exception) to be null (no matter how occasionally) then you should have a test for that:

if (str.Element("title") != null)
{
    // your existing code.
}

If you are not expecting it to be null and it truly is an exceptional circumstance then having a try catch is the only other way to stop the method crashing.

Upvotes: 3

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