c# xml.Load() locking file on disk causing errors

m3ntat picture m3ntat · Nov 28, 2009 · Viewed 15.4k times · Source

I have a simple class XmlFileHelper as follows:

public class XmlFileHelper
{
    #region Private Members

    private XmlDocument xmlDoc = new XmlDocument();
    private string xmlFilePath;

    #endregion

    #region Constructor

    public XmlFileHelper(string xmlFilePath)
    {
        this.xmlFilePath = xmlFilePath;
        xmlDoc.Load(xmlFilePath);
    }

    #endregion

    #region Public Methods

    public XmlNode SelectSingleNode(string xPathQuery)
    {
        return xmlDoc.SelectSingleNode(xPathQuery);
    }

    public string GetAttributeValueByName(XmlNode node, string attributeName)
    {
        return node.Attributes.GetNamedItem(attributeName).Value;
    }

    #endregion

    #region Public Properties

    public string XmlFilePath
    {
        get
        {
            return xmlFilePath;
        }
    }

    #endregion
}

The issue is I am getting the following error on Load:

System.IO.IOException: The process cannot access the file ''C:\CvarUAT\ReportWriterSettings.xml'' **because it is being used by another process**

this occurs when this class is used to by two running instances of a component running in parallel both attempting to load the xml file above, this is legitimate behaviour and required by the application.

I only want to read in the xml off disk once and release any reference to the file on disk and use an in memory representation from that point forward.

I would have assumed Load operates in a readonly fashion and would have no need to lock the file, what is my best way to achieve the desired result and get around this issue?

Thanks

Answer

João Angelo picture João Angelo · Nov 28, 2009

You can do this

using (Stream s = File.OpenRead(xmlFilePath))
{
    xmlDoc.Load(s);
}

instead of

xmlDoc.Load(xmlFilePath);