How to comment out line by line of a XML file in C# with System.XML

Question

I need to comment and uncomment a XML node with child nodes in a file using System.XML.

Starting XML:

<?xml version="1.0" encoding="utf-8"?>
    <test>
    <!--comment...-->    
        <childTest>
            <childchildTest>5<childchildTest/>
        </childTest>
    </test>

Commenting the whole node wouldn't be a problem and easy to achieve like in this example. But my problem is that I've already got some comments inside the node and nested comments aren't allowed per XML rules.

That means I would have to comment out line by line of the XML file so I would not destroy the XML file structure with nested comments.

Desired output:

<?xml version="1.0" encoding="utf-8"?>
<!--    <test> -->
    <!--comment...-->    
<!--        <childTest> -->
<!--           <childchildTest>5<childchildTest/> -->
<!--        </childTest> -->
<!--    </test> -->

Is it possible to achieve this with System.XML or would I have to do this with regex for example?

Michał Turczyn · Accepted Answer · 2019-01-11T10:15:10.610

3

Assuming you have this XML well-organised in a file (meaning each node is on its own line, as you presented) you could use this one-liner:

File.WriteAllLines("path to new XML file", File.ReadAllLines("path to XML file").Select(line => line.Trim().StartsWith("<!--") ? line : $"<!--{line}-->"));

This part line.Trim().StartWith("" means if line is a comment (starts with <!--) then don't comment it, otherwise, do it.

edited Jan 11 '19 at 10:15

answered Jan 11 '19 at 09:50

Michał Turczyn

32,028
14
47
69

1

This ignores OP's problem with "nested" comments. – Rand Random Jan 11 '19 at 10:02
@RandRandom No, it comments line by line. Try the code. – Michał Turczyn Jan 11 '19 at 10:07
I did try it - your code will comment each line - but it shouldn't comment lines that already have a comment - since doing this (nesting) is invalid XML. Your code will result in `-->` that's invalid. – Rand Random Jan 11 '19 at 10:09
1

@RandRandom Aah, you're right!! Corrected answer :) – Michał Turczyn Jan 11 '19 at 10:10
1

Should probably trim the line, incase of leading whitespaces. – Rand Random Jan 11 '19 at 10:12
@RandRandom In OPs desired result it includes spaces in comments. – Michał Turczyn Jan 11 '19 at 10:12
2

I only meant for the check with `StartsWith` since it will now result in false. – Rand Random Jan 11 '19 at 10:13
@RandRandom I see what you mean, eagle-eye :) Thanks. – Michał Turczyn Jan 11 '19 at 10:15
1

Now I could start complaing that your code isn't respecting multiline comments, but maybe thats enough for OP. :) – Rand Random Jan 11 '19 at 10:23
thanks for your answer @MichałTurczyn this one liner is nice I'm currently trying to modify Manojs answer for some further needs - if it won't work out I will try it out with your approach. Since I dont need to comment out the whole XML, just a section of my whole (bigger) XML, line by line. But I dont want the whole code done by you just needed an approach - so thanks again :) – C.User Jan 11 '19 at 10:24

score 1 · Answer 2 · answered Jan 11 '19 at 09:49

1

In my opinion, there is no framework method which provides this functionality. You can read XML file lines and then create new files which has comments for every line as shown in below code.

// Create a string array with the lines of text
string[] lines = File.ReadAllLines(path-of-file);

// Write the string array to a new file named "ouput.xml".
using (StreamWriter outputFile = new StreamWriter(Path.Combine(mydocpath,"output.xml"))) {
    foreach (string line in lines)
        outputFile.WriteLine("<!--" + line + "-->");
}

answered Jan 11 '19 at 09:49

Manoj Choudhari

5,277
2
26
37

2

This ignores OP's problem with "nested" comments. – Rand Random Jan 11 '19 at 10:02
thanks for your answer, this approach is modifiable for my needs. – C.User Jan 11 '19 at 10:20

How to comment out line by line of a XML file in C# with System.XML

2 Answers2