NameValueSectionHandler - can i use this section type for writing back to the application config file?

Question

back to the topic of why didn\'t .net provide a simple (i don\'t want to implement \"ConfigurationSection\" \"ConfigurationElement\" \"ConfigurationProperty\" for 2 val

Answer 1

• No - NameValueSectionHandler does not assist the user in 'creating' the Xml that will be written to the app.config file.

Fire up reflector and take a look at the following method on System.Configuration.NameValueSectionHandler : internal static object CreateStatic(object parent, XmlNode section, string keyAttriuteName, string valueAttributeName).

Linda Liu from Microsoft Online Community Support gives some great information about NameValueSectionHandler, IConfigurationSectionHandler, and why a DefaultSection instance will be returned from Configuration.GetSection(string) in a discussion at the EggHeadCafe forums: Backwards compatibility of System.Configuration.Configuration.

It is technically possible to read, and create this information, but I recommend you not cause yourself more pain than you must by interacting at this extremely low level of the Configuration API. Please use the below code for Educational purposes only. I highly encourage you to use one of the methods like what Richard mentioned using the declarative style for creating a custom ConfigurationSection

app.config

    
        

    
    
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You could read this configuration section, but it's not good for your mental health.

Sample C# Code - Stick this inside your void Main(string[] args) and smoke it.

// Read configuration
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
ConfigurationSection readableSection = config.GetSection("SingleTag");
string readableSectionRawXml = readableSection.SectionInformation.GetRawXml();
XmlDocument readableSectionRawXmlDocument = new XmlDocument();
readableSectionRawXmlDocument.Load(new StringReader(readableSectionRawXml));
SingleTagSectionHandler readableSectionHandler = new SingleTagSectionHandler();
Hashtable result = (Hashtable)readableSectionHandler.Create(null, null, readableSectionRawXmlDocument.DocumentElement);
foreach (string item in result.Keys)
{
    Console.WriteLine("{0}\t=\t{1}", item, result[item]);
}

// Create similar configuration section
Hashtable mySettings = new Hashtable();
mySettings.Add("key1", "value1:" + DateTime.Now);
mySettings.Add("key2", "value2:" + DateTime.Now);
mySettings.Add("key3", "value3:" + DateTime.Now);
mySettings.Add("keynull", null);
mySettings.Add("key4", "value4:" + DateTime.Now);
string rawData = string.Empty;
XmlDocument writableSectionXmlDocument = new XmlDocument();
XmlElement rootElement = writableSectionXmlDocument.CreateElement("CreateSingleTag");
foreach (var item in mySettings.Keys)
{
    if (mySettings[item] != null)
    {
        rootElement.SetAttribute(item.ToString(), mySettings[item].ToString());
    }
}
writableSectionXmlDocument.AppendChild(rootElement);

if (config.Sections.Get("CreateSingleTag") == null)
{
    ConfigurationSection writableSection = new DefaultSection();
    writableSection.SectionInformation.SetRawXml(writableSectionXmlDocument.OuterXml);
    config.Sections.Add("CreateSingleTag", writableSection);
}
else
{
config.Sections["CreateSingleTag"].SectionInformation.SetRawXml(writableSectionXmlDocument.OuterXml);
}

config.Save();

For completeness sake - you need the following usings

using System;
using System.Collections;
using System.Configuration;
using System.IO;
using System.Xml;

and a reference to at least the following assemblies

System
System.Configuration
System.Xml