Update existing XML file in C#

Question

I tried to update this small xml example file without success. It is not giving me any error but the file remains unchanged. Any ideas ?

Thanks

XML Sample:

<test>
  <user>John Doe</user>
  <user>Jane Doe</user>
</test>

C# Code

 XmlDocument doc = new XmlDocument();
    doc.Load("../../../test.xml");

    XmlNode sNode = doc.SelectSingleNode("/test/user");
    XmlAttribute users = sNode.Attributes["user"];

    if (users != null)
    {             
            string currentValue = users.Value;            
            if (string.IsNullOrEmpty(currentValue))
            {
            users.Value = "Thomas";
            }
    }
    doc.Save("../../../test1.xml");

`sNode.Attributes["user"]` your xml doesn't contain a user attribute — DanielS, Sep 15 '16 at 19:36

Timon Post · Answer 1 · 2016-09-15T19:43:22.000

1

This is how I changed the value inside a node:

        XmlNode node= _doc.SelectSingleNode("test/user[1]"); // [index of user node]
        node.InnerText = value;
        _doc.Save(@"path");

edited Sep 15 '16 at 19:43

answered Sep 15 '16 at 19:38

Timon Post

2,779
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score 1 · Answer 2 · answered Sep 15 '16 at 20:00

1

This works now perfectly:

XmlDocument doc = new XmlDocument();
doc.Load("../../../test.xml");

XmlNode node = doc.SelectSingleNode("test/user[1]"); // [index of user node]
node.InnerText = "thomas";

doc.Save("../../../test1.xml");

Thank you

answered Sep 15 '16 at 20:00

Thomas

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score 0 · Answer 3 · answered Sep 15 '16 at 19:38

0

Your user node doesn't have any attribute in your XML file :

So users is null here :

 XmlAttribute users = sNode.Attributes["user"];

You should test if sNode != null

 if (sNode != null){
    ....
 }

answered Sep 15 '16 at 19:38

Quentin Roger

6,410
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36

Thank you, I just noticed that I don`t have an attribute there, but the solution from Timon Post was what I was looking for and it works perfectly. – Thomas Sep 15 '16 at 19:54

Update existing XML file in C#

3 Answers3