Windows API are the
dlls that are the part of microsoft windows operation system
There are many task in the application development that
are very difficult to handle in your own code for example if we have need to
change background of your desktop via your application than what you do? Simple
you can use User32 windows api for that. .Net framework use plateform invocation
services for it.plateform invocation services is the process by which .net
framework communicate unmanaged code of api.
In this article we will discuss how to use User32 windows api for set the
background of desktop
or desktop wallpaper.
First design windows form
like this:
![form1-in-windows 8.jpg]()
User32 dll has a function 'SystemParametersInfo', and we
can use this function for set and get all the settings controlled by the Windows
Control Panel.
Normally a user would have to choose the Windows Control Panel to view or
change system settings such as granularity, wallpaper, or icon title wrap. And
we will use this function for set the desktop background…
Code:
Define function SystemParametersInfo:
Private Declare
Function SystemParametersInfo
Lib "user32"
Alias "SystemParametersInfoA"
(ByVal uAction As
Integer, ByVal
uParam As Integer,
ByVal lpvParam As
String, ByVal
fuWinIni As Integer)
As Integer
'Declare two constant
Private Const
SETDESKWALLPAPER = 20
Private Const
UPDATEINIFILE = &H1
code for showing preview
in picture box:
Private Sub
btnbrowse_Click(ByVal sender
As System.Object,
ByVal e As System.EventArgs)
Handles btnbrowse.Click
Dim dlg As
New OpenFileDialog
dlg.Title =
"Choose Desktop background image"
dlg.Filter =
""
If dlg.ShowDialog =
Windows.Forms.DialogResult.OK Then
TextBoxLocation.Text = dlg.FileName
PictureBox1.BackgroundImage = Image.FromFile(dlg.FileName)
PictureBox1.BackgroundImageLayout = ImageLayout.Stretch
End If
End Sub
Function call :
Private Sub
btnApply_Click(ByVal sender
As System.Object,
ByVal e As System.EventArgs)
Handles btnApply.Click
SystemParametersInfo(SETDESKWALLPAPER, 0, TextBoxLocation.Text, UPDATEINIFILE)
End Sub