Thay đổi hình nền máy tính để bàn bằng cách sử dụng mã trong .NET

Question

Làm cách nào để thay đổi hình nền màn hình bằng Mã C#?

Answer 1

Dưới đây là một lớp học kéo mạnh từ một ứng dụng tôi đã viết một hoặc hai năm trước:

public sealed class Wallpaper 
{ 
    Wallpaper() { } 

    const int SPI_SETDESKWALLPAPER = 20; 
    const int SPIF_UPDATEINIFILE = 0x01; 
    const int SPIF_SENDWININICHANGE = 0x02; 

    [DllImport("user32.dll", CharSet = CharSet.Auto)] 
    static extern int SystemParametersInfo(int uAction, int uParam, string lpvParam, int fuWinIni); 

    public enum Style : int 
    { 
     Tiled, 
     Centered, 
     Stretched 
    } 

    public static void Set(Uri uri, Style style) 
    { 
     System.IO.Stream s = new System.Net.WebClient().OpenRead(uri.ToString()); 

     System.Drawing.Image img = System.Drawing.Image.FromStream(s); 
     string tempPath = Path.Combine(Path.GetTempPath(), "wallpaper.bmp"); 
     img.Save(tempPath, System.Drawing.Imaging.ImageFormat.Bmp); 

     RegistryKey key = Registry.CurrentUser.OpenSubKey(@"Control Panel\Desktop", true); 
     if (style == Style.Stretched) 
     { 
      key.SetValue(@"WallpaperStyle", 2.ToString()); 
      key.SetValue(@"TileWallpaper", 0.ToString()); 
     } 

     if (style == Style.Centered) 
     { 
      key.SetValue(@"WallpaperStyle", 1.ToString()); 
      key.SetValue(@"TileWallpaper", 0.ToString()); 
     } 

     if (style == Style.Tiled) 
     { 
      key.SetValue(@"WallpaperStyle", 1.ToString()); 
      key.SetValue(@"TileWallpaper", 1.ToString()); 
     } 

     SystemParametersInfo(SPI_SETDESKWALLPAPER, 
      0, 
      tempPath, 
      SPIF_UPDATEINIFILE | SPIF_SENDWININICHANGE); 
    } 
} 

tôi đã không kiểm tra nó rộng rãi, vì vậy sử dụng có nguy cơ của riêng bạn.

Answer 2

câu trả lời Tweaking Neal N đối với GIF:

private const int SPI_SETDESKWALLPAPER = 20; 
private const int SPIF_UPDATEINIFILE = 0x01; 
private const int SPIF_SENDWININICHANGE = 0x02; 

[DllImport("user32.dll", CharSet = CharSet.Auto)] 
private static extern int SystemParametersInfo(int uAction, int uParam, string lpvParam, int fuWinIni); 

public enum Style : int 
{ 
    Tiled, 
    Centered, 
    Stretched 
} 

/// <summary> 
/// Loops numFrames times, animating the desktop background as the given gif. 
/// Remember this will sorta bog down your computer, and probably isn't best to be running 24/7. 
/// If numFrames is negative this will loop forever 
/// </summary> 
/// <param name="gifPath">The gif to be animated</param> 
/// <param name="transparencyReplace">If the gif has transparency, it will be "replaced" with this color.</param> 
/// <param name="framesPerSecond">How many frames to play per second. This is a max: most likely it will be a little slower than this especially at first.</param> 
/// <param name="style">Whether to tile, center, or stretch each gif frame as it's played.</param> 
/// <param name="numFrames">The number of frames to play. If negative, this method will loop forever.</param> 
public static void SetDesktopBackgroundAsGifAsync(string gifPath, System.Drawing.Color transparencyReplace, int framesPerSecond, Style style, int numFrames) 
{ 
    Thread workerThread = new Thread(() => SetDesktopBackgroundAsGif(gifPath, transparencyReplace, framesPerSecond, style, numFrames)); 
    workerThread.Start(); 
} 

/// <summary> 
/// Loops numFrames times, animating the desktop background as the given gif. 
/// Remember this will sorta bog down your computer, and probably isn't best to be running 24/7. 
/// If num frames is negative this will loop forever. 
//// <summary> 
/// <param name="gifPath">The gif to be animated</param> 
/// <param name="backgroundImage">Image to render the gif on top of (because of transparency)</param> 
/// <param name="framesPerSecond">How many frames to play per second. This is a max: most likely it will be a little slower than this.</param> 
/// <param name="style">Whether to tile, center, or stretch each gif frame as it's played.</param> 
/// <param name="numFrames">The number of frames to play. If negative, this method will loop forever.</param> 
public static void SetDesktopBackgroundAsGifAsync(string gifPath, System.Drawing.Image backgroundImage, int framesPerSecond, Style style, int numFrames) 
{ 
    Thread workerThread = new Thread(() => SetDesktopBackgroundAsGif(gifPath, backgroundImage, framesPerSecond, style, numFrames)); 
    workerThread.Start(); 
} 

/// <summary> 
/// Loops numFrames times, animating the desktop background as the given gif. 
/// Remember this will sorta bog down your computer, and probably isn't best to be running 24/7. 
/// if numFrames is negative this will loop forever 
/// </summary> 
/// <param name="gifPath">The gif to be animated</param> 
/// <param name="transparencyReplace">If the gif has transparency, it will be "replaced" with this color.</param> 
/// <param name="framesPerSecond">How many frames to play per second. This is a max: most likely it will be a little slower than this.</param> 
/// <param name="style">Whether to tile, center, or stretch each gif frame as it's played.</param> 
/// <param name="numFrames">The number of frames to play. If negative, this method will loop forever.</param> 
public static void SetDesktopBackgroundAsGif(string gifPath, System.Drawing.Color transparencyReplace, int framesPerSecond, Style style, int numFrames) 
{ 
    if (!File.Exists(gifPath)) 
     throw new Exception("Given gif: '" + gifPath + "' not found"); 

    FileStream gifFile = new FileStream(gifPath, FileMode.Open); 

    GifBitmapDecoder gifDecoder = new GifBitmapDecoder(gifFile, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad); 

    if (gifDecoder.Frames.Count == 0) 
     throw new Exception("No frames in given gif"); 

    Bitmap backgroundImage = new Bitmap(gifDecoder.Frames[0].PixelWidth, gifDecoder.Frames[0].PixelHeight, System.Drawing.Imaging.PixelFormat.Format32bppArgb); 

    using(Graphics g = Graphics.FromImage(backgroundImage)) 
    { 
     g.FillRectangle(new System.Drawing.SolidBrush(transparencyReplace), 0, 0, gifDecoder.Frames[0].PixelWidth, gifDecoder.Frames[0].PixelHeight); 
    } 

    gifFile.Close(); 

    SetDesktopBackgroundAsGif(gifPath, backgroundImage, framesPerSecond, style, numFrames); 
} 

/// <summary> 
/// Loops infinitely, animating the desktop background as the given gif. 
/// Remember this will sorta bog down your computer, and probably isn't best to be running 24/7. 
/// </summary> 
/// <param name="gifPath">The gif to be animated</param> 
/// <param name="backgroundImage">Image to render the gif on top of (because of transparency)</param> 
/// <param name="framesPerSecond">How many frames to play per second. This is a max: most likely it will be a little slower than this.</param> 
/// <param name="style">Whether to tile, center, or stretch each gif frame as it's played.</param> 
/// <param name="numFrames">The number of frames to play. If negative, this method will loop forever.</param> 
private static void SetDesktopBackgroundAsGif(string gifPath, System.Drawing.Image backgroundImage, int framesPerSecond, Style style, int numFrames) 
{ 
    if (!File.Exists(gifPath)) 
     throw new Exception("Given gif: '" + gifPath + "' not found"); 

    FileStream gifFile = new FileStream(gifPath, FileMode.Open); 

    GifBitmapDecoder gifDecoder = new GifBitmapDecoder(gifFile, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad); 

    if (gifDecoder.Frames.Count == 0) 
     throw new Exception("No frames in given gif"); 

    Console.WriteLine("Saving frames to temporary files:"); 

    int numFramesSoFar = 0; 

    for (int i = 0; i < gifDecoder.Frames.Count; i++) 
    { 
     BitmapFrame gifFrame = gifDecoder.Frames[i]; 
     PngBitmapEncoder pngEncoder = new PngBitmapEncoder(); 
     pngEncoder.Frames.Add(gifFrame); 
     MemoryStream pngStream = new MemoryStream(); 
     pngEncoder.Save(pngStream); 
     Image frameImage = Image.FromStream(pngStream); 
     Bitmap bmp = new Bitmap(frameImage.Width, frameImage.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb); 
     using (Graphics g = Graphics.FromImage(bmp)) 
     { 
      g.DrawImage(backgroundImage, 0, 0); 
      g.DrawImageUnscaled(frameImage, 0, 0); 
     } 
     string tempPath = Path.Combine(Path.GetTempPath(), gifPath + i + ".bmp"); 
     bmp.Save(tempPath, System.Drawing.Imaging.ImageFormat.Bmp); 

     Console.WriteLine("Saved frame " + i); 

     numFramesSoFar++; 

     if (numFrames >= 0 && numFramesSoFar >= numFrames) break; 
    } 

    Console.WriteLine("Setting frames to desktop background at about " + framesPerSecond + " FPS"); 

    // 1.0/... to convert to seconds per frame (instead of frames per second) 
    // * 1000 to convert to milliseconds per frame 
    // * 1000 to convert to microseconds per frame 
    // * 10 to convert to 0.1s of microseconds per frame = 100s of nanoseconds per frame 
    long ticksBetweenFrames = (long)Math.Round(1.0/framesPerSecond) * 1000*1000*10; 

    Stopwatch timer = new Stopwatch(); 
    timer.Start(); 

    numFramesSoFar = 0; 

    while(numFrames < 0 || numFramesSoFar < numFrames) 
    { 
     for (int i = 0; i < gifDecoder.Frames.Count; i++) 
     { 
      // Sleep until we're at the desired frame rate, if needed. 
      if(ticksBetweenFrames > timer.ElapsedTicks) 
       Thread.Sleep(new TimeSpan(Math.Max(0, ticksBetweenFrames - timer.ElapsedTicks))); 

      timer.Restart(); 

      // From http://stackoverflow.com/a/1061682/2924421 

      string filePath = Path.Combine(Path.GetTempPath(), "wallpaper" + i + ".bmp"); 

      RegistryKey key = Registry.CurrentUser.OpenSubKey(@"Control Panel\Desktop", true); 

      if (style == Style.Stretched) 
      { 
       key.SetValue(@"WallpaperStyle", 2.ToString()); 
       key.SetValue(@"TileWallpaper", 0.ToString()); 
      } 

      if (style == Style.Centered) 
      { 
       key.SetValue(@"WallpaperStyle", 1.ToString()); 
       key.SetValue(@"TileWallpaper", 0.ToString()); 
      } 

      if (style == Style.Tiled) 
      { 
       key.SetValue(@"WallpaperStyle", 1.ToString()); 
       key.SetValue(@"TileWallpaper", 1.ToString()); 
      } 

      SystemParametersInfo(SPI_SETDESKWALLPAPER, 
       0, 
       filePath, 
       SPIF_UPDATEINIFILE | SPIF_SENDWININICHANGE); 

      numFramesSoFar++; 

      if (numFrames >= 0 && numFramesSoFar >= numFrames) break; 
     } 
    } 

    gifFile.Close(); 
} 

Cũng lưu ý rằng bạn cần phải sử dụng:

using Microsoft.Win32; 
using System; 
using System.Collections.Generic; 
using System.Diagnostics; 
using System.Drawing; 
using System.IO; 
using System.Linq; 
using System.Runtime.InteropServices; 
using System.Text; 
using System.Threading; 
using System.Threading.Tasks; 
using System.Windows.Media; 
using System.Windows.Media.Imaging; 

Cuối cùng, nhấp chuột phải vào dự án của bạn, Add Reference, và (trong Assemblies và khung) thêm bản trình bày Core, System.Xaml và WindowsBase.

Sau đó nhấp chuột phải vào Dự án của bạn và đi vào Thuộc tính và đảm bảo Khung mục tiêu là .Net Framework 4.5. Nếu bạn thay đổi điều này, bạn có thể cần phải khởi động lại Visual Studio.

Answer 3

Căn cứ trên this useful answer, tôi cũng đã thực hiện my own app để đặt độ phân giải màn hình phù hợp với phông nền.

Nhưng cài đặt đăng ký sai. Dưới đây là các giá trị chính xác (được thử nghiệm trên Win 7, Win 8.1, Win 10).

if (style == Style.Fill) 
{ 
    key.SetValue(@"WallpaperStyle", 10.ToString()); 
    key.SetValue(@"TileWallpaper", 0.ToString()); 
} 
if (style == Style.Fit) 
{ 
    key.SetValue(@"WallpaperStyle", 6.ToString()); 
    key.SetValue(@"TileWallpaper", 0.ToString()); 
} 
if (style == Style.Span) // Windows 8 or newer only! 
{ 
    key.SetValue(@"WallpaperStyle", 22.ToString()); 
    key.SetValue(@"TileWallpaper", 0.ToString()); 
} 
if (style == Style.Stretch) 
{ 
    key.SetValue(@"WallpaperStyle", 2.ToString()); 
    key.SetValue(@"TileWallpaper", 0.ToString()); 
} 
if (style == Style.Tile) 
{ 
    key.SetValue(@"WallpaperStyle", 0.ToString()); 
    key.SetValue(@"TileWallpaper", 1.ToString()); 
} 
if (style == Style.Center) 
{ 
    key.SetValue(@"WallpaperStyle", 0.ToString()); 
    key.SetValue(@"TileWallpaper", 0.ToString()); 
}