Allows to get device ppi in C#

GetDevicePPI.cs

    class Program
    {
        [DllImport("gdi32.dll")]
        static extern int GetDeviceCaps(IntPtr hdc, int nIndex);

        [DllImport("user32.dll")]
        static extern IntPtr GetDC(IntPtr hWnd);

        /// <summary>
        /// Logical pixels inch in X
        /// </summary>
        const int LOGPIXELSX = 88;
        /// <summary>
        /// Logical pixels inch in Y
        /// </summary>
        const int LOGPIXELSY = 90;

        static void Main(string[] args)
        {
            IntPtr hdc = GetDC(IntPtr.Zero);

            Console.WriteLine(GetDeviceCaps(hdc, LOGPIXELSX));
            // or
            Console.WriteLine(GetDeviceCaps(hdc, LOGPIXELSY));
            //Console.ReadKey();
        }
    }