changing background

changing background

• devinr

  Yes, Windows doesn't like to deal with .jpeg files, just .bmp files. The shell can, it offers the IActiveDesktop::SetWallpaper() method. Unfortunately, the COM component that implements this method (shell32.dll) doesn't export the IActiveDesktop interface so you don't have a declaration available for it to use in your program. That is what makes dealing with the shell so difficult in .NET, we need a Primary Interop Assembly for the shell but none is available (AFAIK). I hope MSFT is paying attention here.
  
  A workaround for you is to convert the .jpeg file to a .bmp file yourself. Here's code to do this:
  
  Imports System.Runtime.InteropServices
  Imports System.Drawing
  
  Module Module1
  Private Declare Auto Function SystemParametersInfo Lib "user32.dll" (ByVal uAction As Integer, ByVal uParam As Integer, ByVal szImagePath As String, ByVal fuWinIni As Integer) As Boolean
  Private Const SPI_SETDESKWALLPAPER As Integer = &H14
  Private Const SPIF_UPDATEINIFILE As Integer = &H1
  Private Const SPIF_SENDCHANGE As Integer = &H2
  
  Public Function ChangeWallpaper(ByVal path As String) As Boolean
  path = ConvertBitmap(path)
  Return SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, path, SPIF_UPDATEINIFILE Or SPIF_SENDCHANGE)
  End Function
  
  Private Function ConvertBitmap(ByVal srce As String) As String
  '--- Convert image file <srce> to a bitmap file, stored in My Pictures
  Dim sbmp As New Bitmap(srce)
  Dim dbmp As New Bitmap(sbmp.Width, sbmp.Height, Imaging.PixelFormat.Format24bppRgb)
  Dim gr As Graphics = Graphics.FromImage(dbmp)
  gr.DrawImage(sbmp, 0, 0)
  Dim path As String = System.Environment.GetFolderPath(Environment.SpecialFolder.MyPictures)
  path += "\wallpaper.bmp"
  dbmp.Save(path, Imaging.ImageFormat.Bmp)
  sbmp.Dispose()
  dbmp.Dispose()
  Return path
  End Function
  End Module
  
  
  
  

• techlist

  Yeah, it wasn't kosher. Try this instead:
  
  Imports System.Runtime.InteropServices
  Module Module1
  Private Declare Auto Function SystemParametersInfo Lib "user32.dll" (ByVal uAction As Integer, ByVal uParam As Integer, ByVal szImagePath As String, ByVal fuWinIni As Integer) As Boolean
  Private Const SPI_SETDESKWALLPAPER As Integer = &H14
  Private Const SPIF_UPDATEINIFILE As Integer = &H1
  Private Const SPIF_SENDCHANGE As Integer = &H2
  
  Public Function ChangeWallpaper(ByVal path As String) As Boolean
  Return SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, path, SPIF_UPDATEINIFILE Or SPIF_SENDCHANGE)
  End Function
  End Module
  
  
  
  

• Vaish

  I've just given you the code for VB.NET :-)
  
  

• Guns

  jpeg and bitmaps are the supported one's I believe - what happens when you try to give it a jpeg/other file/image formats the code I posted is the code used for this which NoBugz has kindly corrected/made more accurate.

  
  
  

• Chizum

  It works with bmp files but not jpg when you put a jpg file it just uses the default color as your background.
  
  

• AlexBB

  Put this statement at the top of your source code file:
  Imports System.Runtime.Interop
  
  
  

• Warren Trotter

  I believe you may need to do some P/Invoking as there is no direct way of doing it in .NET

  take a look at this, but its in C#

  http://forums.microsoft.com/MSDN/ShowPost.aspx PostID=728979&SiteID=1

  Conversion to VB.NET, by sure to import the System.Runtime.Reflection namespace:

  <DllImport("user32.dll", SetLastError=true)> private shared function SystemParametersInfo (Byval uAction as Integer, ByVal uParam as Integer, ByVal szImagePath as String, ByVal fuWinIni as Integer) as Integer End Function .. .. public function ChangeWallpaper (ByVal path as String) as Boolean   const SPI_SETDESKWALLPAPER as Integer = &h14   const SPIF_UPDATEINIFILE As Integer = &H1 'will make your change permanent in the user profile   const SPIF_SENDCHANGE as Integer = &H2 ' will inform all the windows that something has changed   Dim result as Integer = SystemParametersInfo (SPI_DESKWALLPAPER, 0, path, SPIF_UPDATEINIFILE or SPIF_SENDCHANGE)   return Convert.ToBoolean(result) 'Not sure about this end function

   

  does this help

  
  
  

• Jm Villagra

  i had that, that was all good it is the actual code its self
  
  
  

• JDeciple

  it goes anywhere you wish to execute the code :-)
  
  

• CVPatel

  Im using VB2005 How do I get this to work, please help.
  
  

• Fluxtah

  So all of that goes into the same module And if so do I need to only use it the same way as before
  
  

• Jim P.

  okay thing you i got that to work but is there any wha to make it so that it can use jpeg and other common formats
  
  
• changing background