Reading and parsing an INI file in C#

[ShadowLocke]

This class makes use of System.Collecti ons.Hashtable to enumerate all the settings in an INI file for easy access. Its very simplistic, and completely re-useable. Solid addition for any app that requires a settings file.

using System;
using System.IO;
using System.Collections;
 
public class IniParser
{
    private Hashtable keyPairs = new Hashtable();
    private String iniFilePath;
 
    private struct SectionPair
    {
        public String Section;
        public String Key;
    }
 
    /// <summary>
    /// Opens the INI file at the given path and enumerates the values in the IniParser.
    /// </summary>
    /// <param name="iniPath">Full path to INI file.</param>
    public IniParser(String iniPath)
    {
        TextReader iniFile = null;
        String strLine = null;
        String currentRoot = null;
        String[] keyPair = null;
 
        iniFilePath = iniPath;
 
        if (File.Exists(iniPath))
        {
            try
            {
                iniFile = new StreamReader(iniPath);
 
                strLine = iniFile.ReadLine();
 
                while (strLine != null)
                {
                    strLine = strLine.Trim().ToUpper();
 
                    if (strLine != "")
                    {
                        if (strLine.StartsWith("[") && strLine.EndsWith("]"))
                        {
                            currentRoot = strLine.Substring(1, strLine.Length - 2);
                        }
                        else
                        {
                            keyPair = strLine.Split(new char[] { '=' }, 2);
 
                            SectionPair sectionPair;
                            String value = null;
 
                            if (currentRoot == null)
                                currentRoot = "ROOT";
 
                            sectionPair.Section = currentRoot;
                            sectionPair.Key = keyPair[0];
 
                            if (keyPair.Length > 1)
                                value = keyPair[1];
 
                            keyPairs.Add(sectionPair, value);
                        }
                    }
 
                    strLine = iniFile.ReadLine();
                }
 
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                if (iniFile != null)
                    iniFile.Close();
            }
        }
        else
            throw new FileNotFoundException("Unable to locate " + iniPath);
 
    }
 
    /// <summary>
    /// Returns the value for the given section, key pair.
    /// </summary>
    /// <param name="sectionName">Section name.</param>
    /// <param name="settingName">Key name.</param>
    public String GetSetting(String sectionName, String settingName)
    {
        SectionPair sectionPair;
        sectionPair.Section = sectionName.ToUpper();
        sectionPair.Key = settingName.ToUpper();
 
        return (String)keyPairs[sectionPair];
    }
 
    /// <summary>
    /// Enumerates all lines for given section.
    /// </summary>
    /// <param name="sectionName">Section to enum.</param>
    public String[] EnumSection(String sectionName)
    {
        ArrayList tmpArray = new ArrayList();
 
        foreach (SectionPair pair in keyPairs.Keys)
        {
            if (pair.Section == sectionName.ToUpper())
                tmpArray.Add(pair.Key);
        }
 
        return (String[])tmpArray.ToArray(typeof(String));
    }
 
    /// <summary>
    /// Adds or replaces a setting to the table to be saved.
    /// </summary>
    /// <param name="sectionName">Section to add under.</param>
    /// <param name="settingName">Key name to add.</param>
    /// <param name="settingValue">Value of key.</param>
    public void AddSetting(String sectionName, String settingName, String settingValue)
    {
        SectionPair sectionPair;
        sectionPair.Section = sectionName.ToUpper();
        sectionPair.Key = settingName.ToUpper();
 
        if (keyPairs.ContainsKey(sectionPair))
            keyPairs.Remove(sectionPair);
 
        keyPairs.Add(sectionPair, settingValue);
    }
 
    /// <summary>
    /// Adds or replaces a setting to the table to be saved with a null value.
    /// </summary>
    /// <param name="sectionName">Section to add under.</param>
    /// <param name="settingName">Key name to add.</param>
    public void AddSetting(String sectionName, String settingName)
    {
        AddSetting(sectionName, settingName, null);
    }
 
    /// <summary>
    /// Remove a setting.
    /// </summary>
    /// <param name="sectionName">Section to add under.</param>
    /// <param name="settingName">Key name to add.</param>
    public void DeleteSetting(String sectionName, String settingName)
    {
        SectionPair sectionPair;
        sectionPair.Section = sectionName.ToUpper();
        sectionPair.Key = settingName.ToUpper();
 
        if (keyPairs.ContainsKey(sectionPair))
            keyPairs.Remove(sectionPair);
    }
 
    /// <summary>
    /// Save settings to new file.
    /// </summary>
    /// <param name="newFilePath">New file path.</param>
    public void SaveSettings(String newFilePath)
    {
        ArrayList sections = new ArrayList();
        String tmpValue = "";
        String strToSave = "";
 
        foreach (SectionPair sectionPair in keyPairs.Keys)
        {
            if (!sections.Contains(sectionPair.Section))
                sections.Add(sectionPair.Section);
        }
 
        foreach (String section in sections)
        {
            strToSave += ("[" + section + "]\r\n");
 
            foreach (SectionPair sectionPair in keyPairs.Keys)
            {
                if (sectionPair.Section == section)
                {
                    tmpValue = (String)keyPairs[sectionPair];
 
                    if (tmpValue != null)
                        tmpValue = "=" + tmpValue;
 
                    strToSave += (sectionPair.Key + tmpValue + "\r\n");
                }
            }
 
            strToSave += "\r\n";
        }
 
        try
        {
            TextWriter tw = new StreamWriter(newFilePath);
            tw.Write(strToSave);
            tw.Close();
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }
 
    /// <summary>
    /// Save settings back to ini file.
    /// </summary>
    public void SaveSettings()
    {
        SaveSettings(iniFilePath);
    }
}

Example of usage:

INI File (C:\test.ini):

[AppSettings]
msgPart1=Hello
msgPart2= World
 
[Punctuation]
ex=!

TestApp:

public class TestParser
{
    public static void Main()
    {
        IniParser parser = new IniParser(@"C:\test.ini");
 
        String newMessage;
 
        newMessage = parser.GetSetting("appsettings", "msgpart1");
        newMessage += parser.GetSetting("appsettings", "msgpart2");
        newMessage += parser.GetSetting("punctuation", "ex");
 
        //Returns "Hello World!"
        Console.WriteLine(newMessage);
        Console.ReadLine();
    }
}

[r035198x]

What about comments in the ini file?

[jamesjiao]

If you look through the code - all you have to do is to add another conditional statement as shown here (modified sections in bold):

if (strLine.StartsWith("[") && strLine.EndsWith("]"))
{
  currentRoot = strLine.Substring(1, strLine.Length - 2);
}
else
{
  if (strLine.StartsWith("'")) {
    // assuming comments start with the apostrophe
    // do nothing
  } else 
  {
    keyPair = strLine.Split(new char[] { '=' }, 2);
    SectionPair sectionPair;
    String value = null;
 
    if (currentRoot == null)
      currentRoot = "ROOT";
 
    sectionPair.Section = currentRoot;
    sectionPair.Key = keyPair[0];
 
    if (keyPair.Length > 1)
      value = keyPair[1];
 
    keyPairs.Add(sectionPair, value);
  }
}

[WernerCD]

My kingdom for this parser in a class.cs file...

I'm trying to get this wedged into a class file so I can use it in a few places, since I really do like the layout of it, but when I move it and put it into a namespace it just acts all wonky on me.

[invalidptr]

FYI The whole thing will fail if you have a duplicate key pair. You may want to extend to handle that situation.

[nick1908]

Here is an open source library http://www.multipetros.gr/public-pro...s/confing-dll/ for ini files read/write. It's very well documented and uses indexers (like a dictionary) to contact with the properties. I suggest to give a try!