SetDesktopWallpaper.cs

// http://powershell.com/cs/blogs/tips/archive/2014/01/10/change-desktop-wallpaper.aspx
// slightly modified and converted to application
// How to compile it: save SetDesktopWallpaper.cs to Documents folder, start Powershell and copy and paste following commands
//
//   cd ([System.Environment]::GetFolderPath('MyDocuments'))
//   $compiler = Join-Path ([Runtime.InteropServices.RuntimeEnvironment]::GetRuntimeDirectory()) csc.exe
//   & $compiler /out:SetDesktopWallpaper.exe /target:winexe SetDesktopWallpaper.cs
//
// the command compile SetDesktopWallpaper.cs to SetDesktopWallpaper.exe
// use it as SetDesktopWallpaper.exe <path_to_wallpaper> <wallpaper_style>
//
using System;
using System.Runtime.InteropServices;
using Microsoft.Win32;
namespace Wallpaper
{
	public enum Style : int
	{
		Center, Stretch
	}
	public class Setter {
		public const int SetDesktopWallpaper = 20;
		public const int UpdateIniFile = 0x01;
		public const int SendWinIniChange = 0x02;
		[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
		private static extern int SystemParametersInfo (int uAction, int uParam, string lpvParam, int fuWinIni);
		public static void SetWallpaper ( string path, Wallpaper.Style style ) {
			using (RegistryKey key = Registry.CurrentUser.OpenSubKey("Control Panel\\Desktop", true))
			{
				try {
					switch( style )
					{
						case Style.Stretch :
							key.SetValue(@"WallpaperStyle", "2") ;
							key.SetValue(@"TileWallpaper", "0") ;
							break;
						case Style.Center :
							key.SetValue(@"WallpaperStyle", "1") ;
							key.SetValue(@"TileWallpaper", "0") ;
						break;
					}
				}
				finally {
					key.Close();
				}
			}
			SystemParametersInfo( SetDesktopWallpaper, 0, path, UpdateIniFile | SendWinIniChange );
		}
	}
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main(string[] args)
        {
            string wpath = (args.Length > 0) ? args[0] : "";
            Wallpaper.Style style = Style.Center;
            Enum.TryParse<Wallpaper.Style>((args.Length > 1) ? args[1] : "Center", true, out style);
        	Wallpaper.Setter.SetWallpaper(wpath, style);
		}
	}
}