How to get the child node by specific attribute value in c#

Question

Hi,

I have a xml file looks like this:

<?xml version="1.0" encoding="UTF-8"?>

<gfx xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="Gfx-ME14.xsd">

    <group name="GroupTrip1" visible="true" wallpaper="false" isReferenceObject="false">

        <text name="TextNo1" caption="1"/>

        <text name="TextEU1" caption="ABcd2/-"/>

        <text name="TextCdt1" caption="&gt;="/>

        <text name="TextTag1" caption="ABCDE-01234"/>

        <ellipse name="EllipseFO1" >

            <animations>

                <animateColor expression="{[Trip_v20]iFO_Idx_01.0}" blinkRate="2">

                    <color value="0" />

                    <color value="1" />

                </animateColor>

            </animations>

        </ellipse>

        <text name="TextDes1" caption="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmn"/>

    </group>

//The other 15 groups, "GroupTrip2","GroupTrip3" ,... ,"GroupTrip16".

</gfx>

I have these code to change caption attribute of the node whose name is TextNo1, 2,...16.

                XmlDocument xmlHMI = new XmlDocument();
                xmlHMI.Load("Z:\\myxml.xml");
                XmlNodeList ndlst = xmlHMI.GetElementsByTagName("group");
                for (int i = 1; i < 17; i++)
                {
                    string strname = "TextNo" + i.ToString();
                    foreach (XmlNode grp in ndlst)
                    {
                        foreach (XmlNode chnd in grp.SelectNodes("text"))
                        {
                            if (chnd.Attributes["name"].Value == strname)
                            {
                                chnd.Attributes["caption"].Value = i.ToString();
                            }
                        }
                    }
                }

It works. But I am wondering what the most efficient way is to do it. Thanks.

Answer 1

@Spellman.Lau ,Welcome to Microsoft Q&A, you could try to use XDocument to change caption attribute of the node.

Here is a code example you could refer to.

 XDocument doc = XDocument.Load("test.xml");
 var result = doc.Descendants("text").Where(i => i.Attributes().Select(m => m.Value.ToString()).FirstOrDefault().Contains("TextNo"));
 int n = 1;
 foreach (var item in result)
 {
   item.Attribute("caption").Value = n.ToString();
   n++;
}
doc.Save("test.xml");

Best Regards,

Jack

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Answer 2

Check a variation:

for( int i = 1; i < 17; i++ )
{
    foreach( XmlNode n in xmlHMI.SelectNodes( $"/*/group/text[@name='TextNo{i}']" ) )
    {
        n.Attributes["caption"].Value = i.ToString( );
    }
}

Or maybe:

foreach( XmlNode n in xmlHMI.SelectNodes( "/*/group/text[starts-with(@name, 'TextNo')]" ) )
{
    n.Attributes["caption"].Value = n.Attributes["name"].Value.Substring("TextNo".Length);
}