CODEWITHSUNDEEP
c#app-config
ErikE
ErikE

Reputation: 50251

How to simulate the file attribute of a .config file's appSettings section

Microsoft gives instructions for how to use the file attribute to make a .config file's appSettings section reference another file: For example:

<appSettings file="c:\commonSettings.config">
    <add key="myAppSpecificSetting" value="Setting1" />
</appSettings>

However, this is implemented specifically for only appSettings and isn't some general .config file feature.

Now, I have implemented my own ConfigurationSection, and would like to be able to specify file= just like one can with appSettings. Aside from simply creating the property to match the attribute and retrieve the file name, how can I actually recreate/simulate this functionality in my custom configSection?

Upvotes: 3

Views: 87

Answers (1)

Jacob
Jacob

Reputation: 78890

Thankfully we have the source code now. It looks like it's just something implemented by AppSettingsSection by reading the file system, nothing special you can reuse in your own configuration section.

protected internal override void DeserializeElement(XmlReader reader, bool serializeCollectionKey) 
{
    string ElementName = reader.Name;

    base.DeserializeElement(reader, serializeCollectionKey);
    if ((File != null) && (File.Length > 0)) {
        string sourceFileFullPath;
        string configFileDirectory;
        string configFile;

        // Determine file location
        configFile = ElementInformation.Source;

        if (String.IsNullOrEmpty(configFile)) {
            sourceFileFullPath = File;
        }
        else {
            configFileDirectory = System.IO.Path.GetDirectoryName(configFile);
            sourceFileFullPath = System.IO.Path.Combine(configFileDirectory, File);
        }

        if (System.IO.File.Exists(sourceFileFullPath)) {
            int lineOffset = 0;
            string rawXml = null;

            using (Stream sourceFileStream = new FileStream(sourceFileFullPath, FileMode.Open, FileAccess.Read, FileShare.Read)) {
                using (XmlUtil xmlUtil = new XmlUtil(sourceFileStream, sourceFileFullPath, true)) {
                    if (xmlUtil.Reader.Name != ElementName) {
                        throw new ConfigurationErrorsException(
                                SR.GetString(SR.Config_name_value_file_section_file_invalid_root, ElementName),
                                xmlUtil);
                    }

                    lineOffset = xmlUtil.Reader.LineNumber;
                    rawXml = xmlUtil.CopySection();

                    // Detect if there is any XML left over after the section
                    while (!xmlUtil.Reader.EOF) {
                        XmlNodeType t = xmlUtil.Reader.NodeType;
                        if (t != XmlNodeType.Comment) {
                            throw new ConfigurationErrorsException(SR.GetString(SR.Config_source_file_format), xmlUtil);
                        }

                        xmlUtil.Reader.Read();
                    }
                }
            }

            ConfigXmlReader internalReader = new ConfigXmlReader(rawXml, sourceFileFullPath, lineOffset);
            internalReader.Read();
            if (internalReader.MoveToNextAttribute()) {
                throw new ConfigurationErrorsException(SR.GetString(SR.Config_base_unrecognized_attribute, internalReader.Name), (XmlReader)internalReader);
            }

            internalReader.MoveToElement();

            base.DeserializeElement(internalReader, serializeCollectionKey);
        }
    }
}

Upvotes: 1

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