using System . Runtime . InteropServices;

[ StructLayout ( LayoutKind . Sequential)]

public struct DEVMODE

{

    private const int CCHDEVICENAME = 0x20 ;

    private const int CCHFORMNAME = 0x20 ;

   [ MarshalAs ( UnmanagedType . ByValTStr, SizeConst = 0x20 )]

    public string dmDeviceName;

    public short dmSpecVersion;

    public short dmDriverVersion;

    public short dmSize;

    public short dmDriverExtra;

    public int dmFields;

    public int dmPositionX;

    public int dmPositionY;

    public ScreenOrientation dmDisplayOrientation;

    public int dmDisplayFixedOutput;

    public short dmColor;

    public short dmDuplex;

    public short dmYResolution;

    public short dmTTOption;

    public short dmCollate;

   [ MarshalAs ( UnmanagedType . ByValTStr, SizeConst = 0x20 )]

    public string dmFormName;

    public short dmLogPixels;

    public int dmBitsPerPel;

    public int dmPelsWidth;

    public int dmPelsHeight;

    public int dmDisplayFlags;

    public int dmDisplayFrequency;

    public int dmICMMethod;

    public int dmICMIntent;

    public int dmMediaType;

    public int dmDitherType;

    public int dmReserved1;

    public int dmReserved2;

    public int dmPanningWidth;

    public int dmPanningHeight;

}

[ DllImport ( "user32.dll" )]

public static extern bool EnumDisplaySettings( string lpszDeviceName ,

    int iModeNum, ref DEVMODE lpDevMode);

private void button1_Click( object sender , EventArgs e)

{  

    DEVMODE vDevMode = new DEVMODE ();

    int i = 0 ;

    while (EnumDisplaySettings( null , i, ref vDevMode))

   {

        Console . WriteLine( "Width:{0} Height:{1} Color:{2} Frequency:{3}" ,

           vDevMode . dmPelsWidth,

           vDevMode . dmPelsHeight,

            1 << vDevMode . dmBitsPerPel,

           vDevMode . dmDisplayFrequency

       );

       i ++ ;

   }

}