Reading/writing an INI file

Question

Is there any class in the .NET framework that can read/write standard .ini files:

[Section]
<keyname>=<value>
...

Delphi has the TIniFile component and I want to know if there is anything similar for C#?

Answer 1

Preface

Firstly, read this MSDN blog post on the limitations of INI files. If it suits your needs, read on.

This is a concise implementation I wrote, utilising the original Windows P/Invoke, so it is supported by all versions of Windows with .NET installed, (i.e. Windows 98 - Windows 10). I hereby release it into the public domain - you're free to use it commercially without attribution.

The tiny class

Add a new class called IniFile.cs to your project:

using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;

// Change this to match your program's normal namespace
namespace MyProg
{
    class IniFile   // revision 11
    {
        string Path;
        string EXE = Assembly.GetExecutingAssembly().GetName().Name;

        [DllImport("kernel32", CharSet = CharSet.Unicode)]
        static extern long WritePrivateProfileString(string Section, string Key, string Value, string FilePath);

        [DllImport("kernel32", CharSet = CharSet.Unicode)]
        static extern int GetPrivateProfileString(string Section, string Key, string Default, StringBuilder RetVal, int Size, string FilePath);

        public IniFile(string IniPath = null)
        {
            Path = new FileInfo(IniPath ?? EXE + ".ini").FullName;
        }

        public string Read(string Key, string Section = null)
        {
            var RetVal = new StringBuilder(255);
            GetPrivateProfileString(Section ?? EXE, Key, "", RetVal, 255, Path);
            return RetVal.ToString();
        }

        public void Write(string Key, string Value, string Section = null)
        {
            WritePrivateProfileString(Section ?? EXE, Key, Value, Path);
        }

        public void DeleteKey(string Key, string Section = null)
        {
            Write(Key, null, Section ?? EXE);
        }

        public void DeleteSection(string Section = null)
        {
            Write(null, null, Section ?? EXE);
        }

        public bool KeyExists(string Key, string Section = null)
        {
            return Read(Key, Section).Length > 0;
        }
    }
}

How to use it

Open the INI file in one of the 3 following ways:

// Creates or loads an INI file in the same directory as your executable
// named EXE.ini (where EXE is the name of your executable)
var MyIni = new IniFile();

// Or specify a specific name in the current dir
var MyIni = new IniFile("Settings.ini");

// Or specify a specific name in a specific dir
var MyIni = new IniFile(@"C:\Settings.ini");

You can write some values like so:

MyIni.Write("DefaultVolume", "100");
MyIni.Write("HomePage", "http://www.google.com");

To create a file like this:

[MyProg]
DefaultVolume=100
HomePage=http://www.google.com

To read the values out of the INI file:

var DefaultVolume = MyIni.Read("DefaultVolume");
var HomePage = MyIni.Read("HomePage");

Optionally, you can set [Section]'s:

MyIni.Write("DefaultVolume", "100", "Audio");
MyIni.Write("HomePage", "http://www.google.com", "Web");

To create a file like this:

[Audio]
DefaultVolume=100

[Web]
HomePage=http://www.google.com

You can also check for the existence of a key like so:

if(!MyIni.KeyExists("DefaultVolume", "Audio"))
{
    MyIni.Write("DefaultVolume", "100", "Audio");
}

You can delete a key like so:

MyIni.DeleteKey("DefaultVolume", "Audio");

You can also delete a whole section (including all keys) like so:

MyIni.DeleteSection("Web");

Please feel free to comment with any improvements!