CHANGER LA RESOLUTION DE VOTRE ECRAN, UTILISATION DES API WINDOWS (USER32.DLL)

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;

[StructLayout(LayoutKind.Sequential)]

public struct DEVMODE1 
{
	[MarshalAs(UnmanagedType.ByValTStr,SizeConst=32)] public string dmDeviceName;

	public short  dmSpecVersion;
	public short  dmDriverVersion;
	public short  dmSize;
	public short  dmDriverExtra;
	public int    dmFields;

	public short dmOrientation;
	public short dmPaperSize;
	public short dmPaperLength;
	public short dmPaperWidth;

	public short dmScale;
	public short dmCopies;
	public short dmDefaultSource;
	public short dmPrintQuality;
	public short dmColor;
	public short dmDuplex;
	public short dmYResolution;
	public short dmTTOption;
	public short dmCollate;

	[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)] public string dmFormName;

	public short dmLogPixels;
	public short 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;
};



class User_32
{
	[DllImport("user32.dll")]
	public static extern int EnumDisplaySettings (string deviceName, int modeNum, ref DEVMODE1 devMode );         
	[DllImport("user32.dll")]
	public static extern int ChangeDisplaySettings(ref DEVMODE1 devMode, int flags);

	public const int ENUM_CURRENT_SETTINGS = -1;
	public const int CDS_UPDATEREGISTRY = 0x01;
	public const int CDS_TEST = 0x02;
	public const int DISP_CHANGE_SUCCESSFUL = 0;
	public const int DISP_CHANGE_RESTART = 1;
	public const int DISP_CHANGE_FAILED = -1;

}


namespace NomDuProjet
{
	class CResolution
	{
		public CResolution(int a,int b)
		{
			Screen screen = Screen.PrimaryScreen;
			
			
			int iWidth =a;
			int iHeight =b;
			

			DEVMODE1 dm = new DEVMODE1();
			dm.dmDeviceName = new String (new char[32]);
			dm.dmFormName = new String (new char[32]);
			dm.dmSize = (short)Marshal.SizeOf (dm);

			if (0 != User_32.EnumDisplaySettings (null, User_32.ENUM_CURRENT_SETTINGS, ref dm))
			{
				
				dm.dmPelsWidth = iWidth;
				dm.dmPelsHeight = iHeight;

				int iRet = User_32.ChangeDisplaySettings (ref dm, User_32.CDS_TEST);

				if (iRet == User_32.DISP_CHANGE_FAILED)
				{
					MessageBox.Show("On ne peut proceder au chagement de Resolution");
                                        MessageBox.Show("Description: On ne peut proceder au chagement de Resolution. Desolé pour cette inconvénient.", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
				}
				else
				{
					iRet = User_32.ChangeDisplaySettings (ref dm, User_32.CDS_UPDATEREGISTRY);

					switch (iRet) 
					{
						case User_32.DISP_CHANGE_SUCCESSFUL:
						{
							break;

							// Changé avec succes
						}
						case User_32.DISP_CHANGE_RESTART:
						{
							
							MessageBox.Show("Description: VOus devez demarer votre ordinateur pour appliquer le changement.\n Si vous avez tout probleme aplrés redemarage.\nThen Essayer d'appliquer le Changement de Resolution en 'Safe Mode'.","Information",MessageBoxButtons.OK,MessageBoxIcon.Information);
							break;
							// les series windows 9x, Vous devez redemarer la machine.
						}
						default:
						{
							
							MessageBox.Show("Description: Imposible de changer la Resolution.","Information",MessageBoxButtons.OK,MessageBoxIcon.Information);
							break;
							// Changement echoué...
						}
					}
				}	
			}
		}
	}
}