Refresh Desktop

http://www.vbcity.com/

Författaren till den fetmarkerade koden skriver att bakgrundsbilden skall bytas ut men det gör den inte. Jag ser att skrivbordet blinkar till när jag kör mitt program men bilden byts inte ut förrän jag trycker F5. Kan ni se vad som är fel?

Länk till källkoden på vbcity: Force Background Reload

Imports System.IO
Public Class Form1
    Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
    Public Sub New()
        MyBase.New()
        InitializeComponent()
    End Sub

    [b]Public Declare Function SystemParametersInfo Lib "user32" Alias "SystemParametersInfoA" (ByVal uAction As Long, _
                ByVal uParam As Long, _
                ByVal lpvParam As String, _
                ByVal fuWinIni As Long) As Long
    Public Const SPI_SETDESKWALLPAPER = 20
    Public Const SPIF_UPDATEINIFILE = &H1
    Public Const SPIF_SENDWININICHANGE = &H2[/b]
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(104, 0)
        Me.Name = "Form1"
        Me.Opacity = 0
        Me.ShowInTaskbar = False
        Me.WindowState = FormWindowState.Minimized
    End Sub

#End Region
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        CopyImage()
    End Sub

    [b]Function ChangeWallpaper(ByVal Filename As String)
        SystemParametersInfo(SPI_SETDESKWALLPAPER, 0&, Filename, SPIF_UPDATEINIFILE Or SPIF_SENDWININICHANGE)
    End Function[/b]

    Private Sub CopyImage()
        Dim ArrVars(2)
        ArrVars(0) = "c:\desktopimages\"
        ArrVars(1) = "c:\desktopimages\collection\"
        ArrVars(2) = "\desktopimager.jpg"
        Dim Dir As Directory

        If File.Exists(Dir.GetCurrentDirectory & "\config.cfg") Then
            Dim SR As StreamReader = New StreamReader(Dir.GetCurrentDirectory & "\config.cfg")
            Dim StrCfg As String = Trim(SR.ReadLine) : SR.Close()
            If Int(Len(StrCfg)) = 0 Then File.Delete(Dir.GetCurrentDirectory & "\config.cfg") : GoTo NoCfg

            If Dir.Exists(StrCfg) Then : ArrVars(1) = StrCfg
            Else
                If Dir.Exists(Mid(StrCfg, 1, 2)) And Not Int(Len(StrCfg)) = 2 Then
                    Dir.CreateDirectory(StrCfg)
                    ArrVars(1) = StrCfg
                End If
            End If
        End If

NoCfg:
        If Dir.Exists(ArrVars(0)) Then
DirExists:
            If Dir.Exists(ArrVars(1)) Then
CollectorExists:
                Dim ArrFiles = Dir.GetFiles(ArrVars(1), "*.jpg")
                If Int(UBound(ArrFiles)) > -1 Then
                    Randomize()
                    File.Copy(ArrFiles(Int(Rnd() * (UBound(ArrFiles) + 1))), ArrVars(0) & ArrVars(2), True)
                End If
            Else
                Dir.CreateDirectory(ArrVars(1)) : GoTo CollectorExists
            End If
        Else
            Dir.CreateDirectory(ArrVars(0)) : GoTo DirExists
        End If
        [b]ChangeWallpaper("c:\desktopimages\desktopimager.jpg")[/b]
        Application.Exit()
    End Sub
End Class

Jag fortsatte söka och fann då en annan sida på vbcity.com Efter lite pillande blev resultatet detta:

Imports System
Imports System.IO
Imports System.Drawing
Imports System.Windows.Forms
Public Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()
        InitializeComponent()
    End Sub

    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    Public Declare Function SystemParametersInfo Lib "user32" Alias "SystemParametersInfoA" (ByVal uAction As Long, _
            ByVal uParam As Long, _
            ByVal lpvParam As String, _
            ByVal fuWinIni As Long) As Long
    Public Const SPI_SETDESKWALLPAPER = 20
    Public Const SPIF_UPDATEINIFILE = &H1
    Public Const SPIF_SENDWININICHANGE = &H2
    Public Const SPIF_SENDCHANGE = 0
    Private components As System.ComponentModel.IContainer

    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 273)
        Me.Name = "Form1"
        Me.Text = "Form1"
    End Sub

#End Region
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ChangeWallPaper(RandomImageFile())
    End Sub

    Private Function RandomImageFile() As String
        Dim ArrVars(2)
        ArrVars(0) = "c:\desktopimages\collection\"
        ArrVars(1) = "\config.cfg"

        Dim Dir As Directory
        Dim ArrFiles = Dir.GetFiles(ArrVars(0).ToLower(), "*.jpg")

        If Int(UBound(ArrFiles)) > -1 Then
            Randomize()
            RandomImageFile = ArrFiles(Int(Rnd() * (UBound(ArrFiles) + 1))).ToString()
        End If
    End Function

    Private Sub ChangeWallPaper(ByVal FileName As String)
        If FileName.Trim = "" Then Exit Sub

        If FileName.LastIndexOf(".bmp") <> -1 Then
            Dim myImage As Image = Image.FromFile(FileName, True)
            FileName = FileName.Substring(0, FileName.IndexOf(".")) & ".jpg"
            myImage.Save(FileName, Imaging.ImageFormat.Jpeg)
            myImage.Dispose()
        End If

        If File.Exists(FileName) Then
            SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, FileName, SPIF_UPDATEINIFILE)
            SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, FileName, SPIF_SENDCHANGE)
        ElseIf Not File.Exists(FileName) Then
            MessageBox.Show("File Not Found", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End If
        Application.Exit()
    End Sub
End Class

Det fungerar dock inte och bilden bytes inte ut. Jag försår inte varför det inte fungerar.