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c#xmlxpathselectsinglenode

Select specific node next to another - C# - SelectSingleNode

I have an XML file that have two nodes with same name, and need to validate if the first one exist. I'm trying to do with SelectSingleNode and I found some XPath examples.

XML File

<root>
    <header/>
    <mensagem>
        <header/>
        <operacoes>
            <operacao>
                <titulo>
            </operacao>
            <operacao>
                <titulo>
            </operacao>
        </operacoes>
    </mensagem>
    <trailer/>
</root>

Code

XmlDocument arquivoXml = new XmlDocument();
arquivoXml.Load(arquivo.ToString());

if (arquivoXml.DocumentElement.SelectSingleNode("root/header") != null)
{
    // Tryed the condition above with XPath "../header" too
    // If first header does exists
}
else
{
    // If first header does not exists
}

The condition always do the same result if I remove one or another node. How can I validate the existence of an specific one?

Thanks

Solution

  • Given your XML, I think you want to check

    if (arquivoXml.SelectSingleNode("root/header") != null)

    or

    if (arquivoXml.DocumentElement.SelectSingleNode("header") != null)

    You do not even need XPath but could use

    if (arquivoXml.DocumentElement["header"] != null)