CODEWITHSUNDEEP
c#xml
Paulus141
Paulus141

Reputation: 5

Reading xml file from specific line

this is my situation:

public static string ReadFromLine(int lineNumber, params string[] searchedAttribute)
{
    //XmlTextReader reader = new XmlTextReader(xmlFilePath);
    XmlReaderSettings settings = new XmlReaderSettings();
    settings.LineNumberOffset = lineNumber;
    settings.DtdProcessing = DtdProcessing.Parse;

    FileStream fs = new FileStream(xmlFilePath, FileMode.OpenOrCreate, FileAccess.Read, FileShare.Read);
    XmlReader reader = XmlReader.Create(fs, settings);

    while (reader.Read())
    {
        if (reader.NodeType == XmlNodeType.Element && reader.Name == searchedAttribute[0] || reader.Name == searchedAttribute[1])
        {
            if(reader.Name == searchedAttribute[0])
                reader.MoveToAttribute(searchedAttribute[0]);
            else
                reader.MoveToAttribute(searchedAttribute[1]);

            string currentAttributeValue = reader.ReadElementString();
            return currentAttributeValue;
        }
    }
    return "notFound";
}

In the method I want to read a xml file from line that is passed in the variable "linenumber".

Unfortunately, despite using my settings according to documentation, my reader starts at line 1 every time.

Appreciate any ideas how to solve it or another solutions.

Upvotes: 0

Views: 791

Answers (1)

György Kőszeg
György Kőszeg

Reputation: 18023

Unfortunately, despite using my settings according to documentation...

There must be some misunderstanding here. An XmlReader always starts from the current position of the passed Stream, TextReader, etc.

All what LineNumberOffset does is just an adjustment of the reported line number (if there is any error during the processing, for example).

A possible (but not quite recommended) solution can be if you embed your FileStream into a StreamReader, read lineNumber of lines, and then create an XmlReader passing the StreamReader at the current position to the XmlReader.Create(TextReader,XmlReaderSettings) overload:

using var stream = File.OpenRead(xmlFilePath);

// skipping lineNumber of lines
var streamReader = new StreamReader(stream);
for (int i = 0; i < lineNumber; i++)
    streamReader.ReadLine();

XmlReader xmlReader = XmlReader.Create(sreamReader, settings);

But in fact a more preferable (and formatting-proof) solution would be to read the whole XML into anXDocument and then navigate in the content by LINQ to XML.

Upvotes: 1

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