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Posted 14 Jul 2003

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An Extension for a Configuration Settings Class in .NET

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4.55/5 (41 votes)
19 Aug 20031 min read
A class to allow easy access and updating to configuration settings for your .NET application

Introduction

In the System.Configuration namespace, you will find a sealed class called ConfigurationSettings which provides access to a static NameValueCollection entitled AppSettings. This ConfigurationSettings class allows you to access information stored in an XML-based configuration file. This file is typically titled the name of your executable followed by a ".config" file extension. The main inherent problem with this class is that your strictly only allowed to read values from configuration file through this class, no updating method is provided. I have addressed this issue below in the following ConfigSettings class. I have also updated the class to implement the IConfigurationSectionHandler interface which I plan on detailing within this article as soon as I have more time (Thanks Heath for the suggestion). Reflector was a big help along with simply reading the documentation. As always, if I left something out, please leave a message at the bottom. Hope this is of some help.

The following namespaces are required:

C#
using System;
using System.IO;
using System.Xml;
using System.Reflection;
using System.Collections;
using System.Globalization;
using System.Configuration;
using System.Collections.Specialized;

The class looks like the following:

C#
namespace Configuration
{
    public class ConfigSettingsSectionHandler : IConfigurationSectionHandler
    {
	static ConfigSettingsSectionHandler(){}

	public object Create(object parent, object configContext, 
                                                   System.Xml.XmlNode section)
	{
	    NameValueCollection col = new NameValueCollection(
	    new CaseInsensitiveHashCodeProvider(CultureInfo.InvariantCulture), 
		   new CaseInsensitiveComparer(CultureInfo.InvariantCulture));

		foreach(XmlNode node in section.ChildNodes)
		{
			switch(node.Name)
			{	
				case "add":
				col.Add(node.Attributes["key"].Value, 
					node.Attributes["value"].Value);
				break;
			}
		}
		return col;
	  }
     }	

public class ConfigSettings	
{
	private string _configfilename, _query, _sectionName;
	private XmlDocument _doc;
	private XmlTextWriter _writer;
	private XmlNodeList _nodes;
	private XmlElement  _appsettings, _node;
	private XmlAttribute _attr1, _attr2;
	private bool _bFileExists;

	public ConfigSettings()
	{
		if(File.Exists(Assembly.GetExecutingAssembly().ToString() + 
                                                               ".exe.config"))
		{
			this.ConfigFileName = 
                   Assembly.GetExecutingAssembly().ToString() + ".exe.config";
			_bFileExists = true;
		}
		else
		{
			_bFileExists = false;
		}
	}

	public ConfigSettings(string ConfigFileName)
	{
		if(File.Exists(ConfigFileName))
		{
			this.ConfigFileName = ConfigFileName;
			_bFileExists = true;
		}
		else
		{
			_bFileExists = false;
		}
	}
		
	public NameValueCollection GetConfig()
	{
		return (NameValueCollection)ConfigurationSettings.GetConfig(
                                                                 SectionName);
	}

	public NameValueCollection GetConfig(string SectionName)
	{
	    return (NameValueCollection)ConfigurationSettings.GetConfig(
                                                                 SectionName);
	}

	public string GetValue(string AttributeName)
	{
		NameValueCollection col = this.GetConfig();
		if(col[AttributeName] != null)
		       return Convert.ToString(col[AttributeName].ToString());
		else
			return String.Empty;
	}

	public void SetValue(string AttributeName, string Value)
	{
	        XmlDocument = new XmlDocument();
		XmlDocument.Load(this.ConfigFileName);
	        Query = "configuration/" + SectionName;
		AppSettingsNode = 
                    (XmlElement)this.XmlDocument.SelectSingleNode(this.Query);
		if(AppSettingsNode == null)
			return;
		Query += "/add[@key='" + AttributeName.ToString() + "']";
		XmlNodeList = this.XmlDocument.SelectNodes(this.Query);
		if(XmlNodeList.Count > 0)
			Node = (XmlElement)XmlNodeList[0];
		else
		{
			Node = this.XmlDocument.CreateElement("add");
			XmlAttribute1 = 
                                      this.XmlDocument.CreateAttribute("key");
			XmlAttribute1.Value = AttributeName.ToString();
			Node.Attributes.SetNamedItem(XmlAttribute1);
			XmlAttribute2 = 
                                    this.XmlDocument.CreateAttribute("value");
			Node.Attributes.SetNamedItem(XmlAttribute2);
			AppSettingsNode.AppendChild(Node);
		}
		Node.Attributes["value"].Value = Value.ToString();
		this.XmlDocument.Save(this.ConfigFileName);
	}

	public void CreateConfigFile(string ConfigFileName, 
                                                           string sectionName)
	{
	        FileStream file = new FileStream(ConfigFileName, 
                                                   System.IO.FileMode.Create);
		file.Close();
		Writer = new XmlTextWriter(ConfigFileName, 
                                                System.Text.Encoding.Unicode);
		Writer.Formatting = Formatting.Indented;
		Writer.WriteRaw("<?xml version=\"1.0\" ?>\n");
		Writer.WriteRaw("<configuration>\n");
		Writer.WriteRaw("<configSections>\n");
		string str = String.Format("<section type="{1}" name="{0}" />\n", 
                       "\"" + sectionName.ToString() + "\"",
             "\"Configuration.ConfigSettingsSectionHandler, Configuration\"");
		Writer.WriteRaw(str.ToString());
		Writer.WriteRaw("</configSections>\n");
		Writer.WriteRaw("<" + sectionName.ToString() + ">\n");
		Writer.WriteRaw("</" ? + sectionName.ToString()>\n");
		Writer.Flush();
		Writer.Close();
		}
	}

        public string ConfigFileName
	{
		get{ return _configfilename;}
		set{ _configfilename = value;}
	}
	public XmlDocument XmlDocument
	{
		get{ return _doc;}
		set{ _doc = value;}
	}
	public XmlTextWriter Writer
	{
		get{ return _writer;}
		set{ _writer = value;}
	}
	public XmlNodeList XmlNodeList
	{
		get{ return _nodes;}
		set{ _nodes = value;}
	}
	public XmlElement AppSettingsNode
	{
		get{ return _appsettings;}
		set{ _appsettings = value;}
	}
	public XmlElement Node
	{
		get{ return _node;}
		set{ _node = value;}
	}
	public string Query
	{
		get{ return _query;}
		set{ _query = value;}
	}
	public XmlAttribute XmlAttribute1
	{
		get{ return _attr1;}
		set{ _attr1 = value;}
	}
	public XmlAttribute XmlAttribute2
	{
		get{ return _attr2;}
		set{ _attr2 = value;}
	}
	public string SectionName
	{
		get{ return _sectionName;}
		set{ _sectionName = value;}
	}
	public bool FileExists
	{
		get{return _bFileExists;}
		set{_bFileExists = value;}
	}
}

Using the Class

To use the class, you will simply do one of the following:

C#
private ConfigSettings config = new ConfigSettings();

and then just use either the GetConfig(), GetValue(), SetValue() methods as such:

C#
  private void Form1_Load(object sender, System.EventArgs e)
  {
     config.ConfigFileName = "Test.exe.config";
     config.SectionName = "ApplicationData";
     string height = config.GetValue("Height");
     if(height != String.Empty)
         this.Height = Convert.ToInt32(height.ToString());

     // or return the whole collection of a particular section.

     NameValueCollection collection = config.GetConfig("ApplicationData");
     if(collection["Width"] != null)
          this.Width = Convert.ToInt32(collection["Width"].ToString());
}
C#
private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
      config.SectionName = "ApplicationData";
      config.SetValue("Height", this.Height.ToString());
      config.SetValue("Width", this.Width.ToString());
}

Conclusion

I just thought I would post the latest updates, there are still many changes to come including a code clean-up as well as more methods to interact with the config file. Let me know what you think.

History

  • 20th August, 2003: Initial post

License

This article has no explicit license attached to it, but may contain usage terms in the article text or the download files themselves. If in doubt, please contact the author via the discussion board below.

A list of licenses authors might use can be found here.

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About the Author

Nick Parker
Software Developer (Senior)
United States United States
Nick graduated from Iowa State University with a B.S. in Management Information System and a minor in Computer Science. Nick works for Zetetic.

Nick has also been involved with the Iowa .NET User Group since it's inception, in particular giving presentations over various .NET topics. Nick was awarded the Visual C# MVP award from Microsoft for four years in a row.

In his mystical spare time he is working on a development project called "DeveloperNotes" which integrates into Visual Studio .NET allowing developers easy access to common code pieces. He is also a fan of using dynamically typed languages to perform unit testing, not to mention how he loves to talk about himself in the third person.

Comments and Discussions

 
Generalproblem with the config file Pin
mark chester goking28-Jan-09 15:30
Membermark chester goking28-Jan-09 15:30 
GeneralRe: problem with the config file Pin
mark chester goking28-Jan-09 16:13
Membermark chester goking28-Jan-09 16:13 
GeneralThis code crashes with a file Browser Pin
Kesler14-Dec-05 9:05
MemberKesler14-Dec-05 9:05 
GeneralExtremely bad code. Pin
Yevgeni Zolotko26-Oct-05 23:41
MemberYevgeni Zolotko26-Oct-05 23:41 
GeneralRe: Extremely bad code. Pin
Herbert Sauro21-Aug-07 11:13
MemberHerbert Sauro21-Aug-07 11:13 
GeneralVery bad code Pin
borner12-Oct-05 23:20
Memberborner12-Oct-05 23:20 
GeneralConstructor don&#180;t works if tool using in dll Pin
gbalog11-Jan-05 7:41
Membergbalog11-Jan-05 7:41 
GeneralRe: Constructor don&#180;t works if tool using in dll Pin
Nick Parker11-Jan-05 8:06
protectorNick Parker11-Jan-05 8:06 
Generalwow your class deletes the config file like a champ ! :mad: Pin
sanjit_rath31-Dec-04 23:02
Membersanjit_rath31-Dec-04 23:02 
GeneralGetValue() and SetValue() problems Pin
Manster13-Apr-04 3:46
MemberManster13-Apr-04 3:46 
GeneralRe: GetValue() and SetValue() problems Pin
Nick Parker13-Apr-04 4:03
protectorNick Parker13-Apr-04 4:03 
GeneralRe: GetValue() and SetValue() problems Pin
Andreas Saurwein27-Apr-04 14:08
MemberAndreas Saurwein27-Apr-04 14:08 
GeneralHave to restart the application to see changes Pin
MaxerCode6-Jan-04 13:10
MemberMaxerCode6-Jan-04 13:10 
GeneralRe: Have to restart the application to see changes Pin
Nick Parker6-Jan-04 17:07
protectorNick Parker6-Jan-04 17:07 
GeneralRe: Have to restart the application to see changes Pin
MaxerCode6-Jan-04 18:09
MemberMaxerCode6-Jan-04 18:09 
QuestionGetValue failing??? Pin
Russq20-Oct-03 2:07
MemberRussq20-Oct-03 2:07 
AnswerRe: GetValue failing??? Pin
Nick Parker20-Oct-03 3:35
protectorNick Parker20-Oct-03 3:35 
GeneralRe: GetValue failing??? Pin
Russq20-Oct-03 3:44
MemberRussq20-Oct-03 3:44 
GeneralRe: GetValue failing??? Pin
Russq20-Oct-03 3:47
MemberRussq20-Oct-03 3:47 
GeneralRe: GetValue failing??? Pin
Russq20-Oct-03 3:49
MemberRussq20-Oct-03 3:49 
GeneralRe: GetValue failing??? Pin
Mithrang17-Nov-03 11:32
MemberMithrang17-Nov-03 11:32 
GeneralRe: GetValue failing??? Pin
Nick Parker17-Nov-03 12:26
protectorNick Parker17-Nov-03 12:26 
GeneralRe: GetValue failing??? Pin
Mithrang17-Nov-03 12:52
MemberMithrang17-Nov-03 12:52 
GeneralRe: GetValue failing??? Pin
Nick Parker17-Nov-03 15:58
protectorNick Parker17-Nov-03 15:58 
GeneralRe: GetValue failing??? Pin
Russq17-Nov-03 22:38
MemberRussq17-Nov-03 22:38 

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