Rotate Windows XP Wallpaper using C# .NET (CSharp)

.:: Rotate Windows XP Wallpaper using C# .NET (CSharp) ::.

Project Name:
JD’s Wallpaper Changer (download complete solution)

Situation:
Displaying wallpaper on the Windows XP desktop can enhance the day-to-day experience of using the PC. However, it’s easy to desktop images to rapidly become stale and maintaining the rotation of images manually can be a pain. Multiple programs are available to help manage desktop wallpaper, but most of these applications are ridden with spy-ware and ad-ware. Based on these factors, I decided to write a basic, simple application to help me rotate images I would like to set as my wallpaper.

Goals:

Rotate wallpaper images on a user set interval
Retrieve available wallpaper images from a single directory allowing for easy maintenance
Facilitate all UI using a NotifyIcon

Underlying Technology:
Capabilities to adjust the Windows desktop wallpaper are not included with v1.1 of the .NET framework. To set the wallpaper, Microsoft has provided an API that requires a series of P/Invoke commands. To eliminate the complication of this process I have created a class file using code from Steve Dunn’s Desktop Decorator. I have created a class file that encapsulates his code. Download Wallpaper.cs by clicking here.

The only UI JD’s Wallpaper Changer utilizes is a NotifyIcon which displays an icon in the SysTray. All commands and messages can be relayed using this technology.

Changing the desktop image on a specified interval requires use of the Timer control.

The Code:

Hiding the Windows From app and displaying only the NotifyIcon:

Hide();
sysTrayIcon.Visible = true;

The first user method launched is retrieving the application settings from the App.config file distributed with the application. App.config has just three settings which are self explanatory.

 
<appSettings> 
  <add key="ImagesDirectory" 
    value="C:\My Documents\My Pictures\Desktop Images" /> 
  <add key="ImageChangeInterval" value="1800" /> 
  <add key="AllowedExtensions" 
    value=".jpg;.jpeg;.gif;.bmp" /> 
</appSettings>

The method to load the application settings:

private int imageChangeInt;
private string imageDirectory;
private string[] allowedExts;
private void loadConfigSettings() 
{
  try 
  {
    imageDirectory = 
      ConfigurationSettings.AppSettings["ImagesDirectory"];
    imageChangeInt = Convert.ToInt32(
      ConfigurationSettings.AppSettings["ImageChangeInterval"]);
    allowedExts = 
      ConfigurationSettings.AppSettings[
   "AllowedExtensions"].Split(
      ";".ToCharArray());
  } 
   catch (Exception ex) 
  {
    MessageBox.Show("The application encountered an error 
      loading the confiuration settings.  
      Please verify the settings in the App.config file",
      "JD's Wallpaper Changer", 
      MessageBoxButtons.OK, MessageBoxIcon.Error);
    Close();
  }
}

Finally, setting the wallpaper is relatively easy:

private void setWallPaper() 
{
  string fileName = getNextImageFilename();
  Wallpaper.Set(new Uri(fileName), Wallpaper.Style.Stretched);    
  if (fileName.Length >= 64)
    sysTrayIcon.Text = 
      string.Format("... {0}", 
      fileName.Substring(fileName.Length - 59, 59));
  else            
    sysTrayIcon.Text = fileName;
}

Links and downloads:
JD’s Wallpaper Changer complete Visual Studio 2003 C# solution download
Code Project