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Custom ConfigurationSection from System.Configuration

Sometimes we forget about System.Configuration. This is plain when you find a project with its custom configuration xml parsing techniques. Maybe we all need to be reminded about System.Configuration. Say you want configuration that looks like this.

<?xml version="1.0" encoding="utf-8" ?>
    <section name="fileCopy" type="LiteMedia.ExampleConfiguration.Configuration.SectionHandler, LiteMedia.ExampleConfiguration"/>
      <directory path="C:\Temp1" />
      <directory path="C:\Temp2" />
      <directory path="D:\Temp1" />
      <directory path="D:\Temp2" />

Let's start by the inner most element, directory. This is a class that inherits from System.Configuration.ConfigurationElement. Each property decorated with the ConfigurationPropertyAttribute is an attribute on the configuration element.

public class Directory : ConfigurationElement
 private const string PathIdentifier = "path";

[ConfigurationProperty(PathIdentifier)] public string Path { get { return (string)this[PathIdentifier]; } set { this[PathIdentifier] = value; } } }

We need a configuration element that can hold a list of other configuration elements. This needs to inherit from System.Configuration.ConfigurationElementCollection. There are some more work involved telling the collection what inner element to expect.

 CollectionType = ConfigurationElementCollectionType.BasicMap,
 AddItemName = AddItemNameIdentifier)]
public class Directories : ConfigurationElementCollection
 public const string AddItemNameIdentifier = "directory";

public override ConfigurationElementCollectionType CollectionType { get { return ConfigurationElementCollectionType.BasicMap; } }

protected override string ElementName { get { return AddItemNameIdentifier; } }

public void Add(Directory directory) { BaseAdd(directory); }

protected override ConfigurationElement CreateNewElement() { return new Directory(); }

protected override object GetElementKey(ConfigurationElement element) { var instance = (Directory)element; return instance.Path; } }

Finally we can create the holder element, the ConfigurationSection. We reference the section from the <configSection> in the App.config file and from here we reach the rest of the configuration. Our configuration section is very simple.

public class SectionHandler : ConfigurationSection
 private const string SourceIdentifier = "source";
 private const string DestinationIdentifier = "destination";

[ConfigurationProperty(SourceIdentifier)] public Directories Source { get { return (Directories)this[SourceIdentifier]; } set { this[SourceIdentifier] = value; } }

[ConfigurationProperty(DestinationIdentifier)] public Directories Destination { get { return (Directories)this[DestinationIdentifier]; } set { this[SourceIdentifier] = value; } } }

Some test program to make sure that it works.

public static void Main(string[] args)
 var configuration = (SectionHandler)ConfigurationManager.GetSection("fileCopy");

Console.WriteLine("SOURCE DIRECTORIES"); foreach (Directory directory in configuration.Source) { Console.WriteLine(directory.Path); }

Console.WriteLine("DESTINATION DIRECTORIES"); foreach (Directory directory in configuration.Destination) { Console.WriteLine(directory.Path); }

Console.ReadLine(); }

You can download the code sample as a zip archive from here.

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