Example of a method in C that reads and writes INI files

Usually C# USES an XML-based configuration file, but you may still need to use the INI file if you need to, for example, accommodate older systems.
However, C# does not have API itself to read and write INI files, and it does so only by calling unmanaged code, the system's own API.

The corresponding read-write methods are GetPrivateProfileString and WritePrivateProfileString, respectively.

Parameters in GetPrivateProfileString:
lpAppName -- name of section
lpKeyName -- name of key
lpDefault -- copy this value to lpReturnedString if lpKeyName is not found
lpReturnedString -- the value used to return the result
nSize -- the character length of lpReturnedString
lpFileName -- INI file name

Parameters in WritePrivateProfileString:
lpAppName -- name of section
lpKeyName -- name of key
lpString -- the value corresponding to lpKeyName
lpFileName -- INI file name

The actual code is as follows:

using System;
using System.Runtime.InteropServices;
using System.Text;
namespace INIDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            WritePrivateProfileString("Demo", "abc", "123", "c:\\demo.ini");
            StringBuilder temp = new StringBuilder();
            GetPrivateProfileString("Demo", "abc", "", temp, 255, "c:\\demo.ini");
            Console.WriteLine(temp);
            Console.ReadLine();
        }
        [DllImport("kernel32", CharSet = CharSet.Unicode, SetLastError = true)]
        private static extern bool WritePrivateProfileString(
            string lpAppName, string lpKeyName, string lpString, string lpFileName);
        [DllImport("kernel32", CharSet = CharSet.Unicode, SetLastError = true)]
        private static extern int GetPrivateProfileString(
            string lpAppName, string lpKeyName, string lpDefault, StringBuilder lpReturnedString,
            int nSize, string lpFileName);
    }
}

The contents of INI file after the program is run are as follows:

[Demo]
abc=123

This is a relatively simple approach, and if you don't want to use unmanaged methods, you can take a more cumbersome approach to the problem.

Because the format of the INI file is fixed, you can do the same thing by writing a corresponding parser, just the usual string manipulation.

If you don't want to do it yourself, don't worry, there's a program out there, Cinchoo framework, to do what you want to do.

And then the one cut becomes easy again.