Delete Node out of an attribute XML C#

Question

as i said in the Title i want to delete the node when i get a specific value out of an attribute. (in this case "install" out of the attribute "dependencyType")

Xml File:

<dependency>
<dependentAssembly dependencyType="preRequisite">
</dependentAssembly>
</dependency>
<dependency>
<dependentAssembly dependencyType="install">
</dependentAssembly>
</dependency>

How it shall look like(after i ran through):

<dependency>
<dependentAssembly dependencyType="preRequisite">
</dependentAssembly>
</dependency>

i want to remove the node (in this case "dependency" when i get in the attribute "dependencytype" the value "install").

i tried two things 1st Code:

private void DeleteXmlPopulates()
    {
        string filepath = "C:\Example\Example.exe.manifest";
        XmlDocument doc = new XmlDocument();
        doc.Load(filePath);
        using (XmlReader reader = XmlReader.Create(filePath))
        {
            while (reader.Read())
            {
                if (reader.Name == "dependency")
                {
                    if (reader.GetAttribute("dependencyType") == "install")
                    {
                       //here i shall get the current Node-name and .Remove(); it
                    }
                }
            }
        }

2nd Code:

        private void DeleteXmlPopulates()
    {
        string filepath = "C:\Example\Example.exe.manifest";
        XmlDocument doc = new XmlDocument();
        doc.Load(filePath);
        var xml = XElement.Load(File.OpenRead(filePath));

        var elementsToDelete = xml.Descendants().Where(x => x.Name == "dependentAssembly" && x.Attribute("dependencyType") != null && x.Attribute("dependencyType").Value == "install");

        foreach (var xElement in elementsToDelete)
        {
            xElement.Remove();
        }
        xml.Save(filePath);
    }

The problem is in the first one is given in the code

The problem is in the second one is that if i get "elementsToDelete" for the foreach-loop and it comes back there arent any "elementsToDelete" so it skips the for each, after all of that, the programm tries to save (xml.save(filepath);) but it gets an exception that its already in use.

What shall i do? Why is it like that?

constructive criticism is Welcome :) correct everytihng you want in my question :) I hope its clear :)

What is the question? You get IOException ? You need to close the FileStream returned by File.OpenRead — Sriram Sakthivel
– Sriram Sakthivel, Commented Aug 5, 2014 at 6:43
Yes i get a System.IO.IOException it sais the File is already in use but if i look up if its in use it sais no — Gentle
– Gentle, Commented Aug 5, 2014 at 6:47

Jon Skeet · Accepted Answer · 2014-08-05 06:47:18Z

2

This is the problem in the second code:

XmlDocument doc = new XmlDocument();
doc.Load(filePath);
var xml = XElement.Load(File.OpenRead(filePath));

For some reason, you're loading the XML document twice in this (and then ignoring doc) - but you're leaving a stream open (the stream returned by File.OpenRead). Change this code to just:

var xml = XElement.Load(filePath);

and it should be fine. You can simplify the rest of the code using the Remove extension method though:

xml.Descendants()
   .Where(x => x.Name == "dependentAssembly" && 
               (string) x.Attribute("dependencyType") == "install")
   .Remove();

Note that casting XAttribute to string just returns null if the attribute doesn't exist (i.e. if you call it with a null reference).

So your who method becomes:

private void DeleteXmlPopulates()
{
    string filepath = "C:\Example\Example.exe.manifest";
    var xml = XElement.Load(filePath);
    xml.Descendants()
       .Where(x => x.Name == "dependentAssembly" && 
                   (string) x.Attribute("dependencyType") == "install")
       .Remove();
    xml.Save(filePath);
}

answered Aug 5, 2014 at 6:47

Jon Skeet

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6 Comments

Gentle Over a year ago

you did a good job but if i use this code on the xml-file it can not be opened :/

Jon Skeet Over a year ago

@Gentle: What do you mean by that? Opened by what? I can't help you without more information.

Gentle Over a year ago

if i go than in the explorer and try to open this file ("c:\exaple\example.exe.manifest") it throws an exception where it sais : "C:\example\Exaple.exe.manifest connot be opened"

Jon Skeet Over a year ago

@Gentle: Well have you tried opening it with notepad, just to see what's in there? It's entirely possible that by removing the element, you've made it invalid - I don't know enough details of manifest files to know. I suggest you change the code to save the modified file to a different filename, so you can then compare the two.

Gentle Over a year ago

In the Code nothing happened. No Problem i'll look for a solution :) Have a great day

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