C call system sound beep~

    public class BeepUp
    {
        /// <param name="iFrequency"> Sound frequency （ from 37Hz To 32767Hz）. stay windows95 Ignored in </param>  
        /// <param name="iDuration"> The duration of the sound , In Milliseconds .</param>  
        [DllImport("Kernel32.dll")] // Introduce namespace  using System.Runtime.InteropServices;  
        public static extern bool Beep(int frequency, int duration);
    }

Calling method ：

BeepUp.Beep(3200, 100);

Sound frequency and The duration of the It can be adjusted by itself .