Question

I have this xml file where I am trying to get some tags from.
Here is the thing… I want to extract the tags that has a specific attribute with a specific value…

Here is an example

<root>
    <input class="x">Data</input>
    <input>Data2</input>
    <input name="y">Data3</input>
    <input class="z">Data4</input>
</root>

I want to get all the “input” tags that has the attribute “class”.

List<XElement> selected = xmlDoc.Descendants("input").Where(t => t.Element("input").Attributes("class") != null).ToList();

but it gives me a null reference exception in the lambda expression… Would you please help me?

Answer 1

t.Attributes("class") will never return null. Use t.Attribute("class") instead (or .Where(t => t.Attributes("class").Any())).

You don’t also need t.Element("input")

var selected = xmlDoc.Descendants("input")
                      .Where(t => t.Attribute("class") != null)
                      .ToList();

or simply

var selected = xmlDoc.XPathSelectElements("//input[@class]").ToList();

with the help of XPATH