MessageBoxA

MessageBoxA.cs

using System.Runtime.InteropServices; // For Pinvoke & Win Api

namespace ConsoleApp1
{
    internal class Program
    {
        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Ansi)]
        public static extern int MessageBoxA(IntPtr hWnd, String text, String caption, uint type);

        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        public static extern int MessageBoxW(IntPtr hWnd, String text, String caption, uint type);


        static void Main(string[] args)
        {
            // Does not display correct
            MessageBoxA(IntPtr.Zero, "фыфыфывы", "фывыфыв", 0);
            // Displays the chars correct notice the W and CharSet difference
            MessageBoxW(IntPtr.Zero, "фыфыфывы", "фывыфыв", 0);
        }
    }
}