Background Switcher

So i currently have this background switcher that works. Thing is, what's supposed to center it in the screen actually tiles it and i don't know why. Ultimately, i'd like to be able to have a separate picture for each monitor, but that's not really necessary. So my question is two fold: One, why doesn't the line indicated below center the background and what should I do instead and two, how do i go about even starting to have two separate pictures, one for each monitor, at the same time with each centered based on the monitor their on. This is important because I have two monitors that are different sizes and something centered in a 1440x900 resolution won't be centered correctly in a 1024x768 resolution.

Code:

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Public Class settings

    Public 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

    Dim Pics As New List(Of String)

    Private Sub settings_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        TimeUnit.SelectedIndex = 1
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim TFPath As String

        FolderBrowserDialog1.ShowDialog()

        TFPath = FolderBrowserDialog1.SelectedPath

        Try

            Dim DInfo As System.IO.DirectoryInfo = System.IO.Directory.GetParent(TFPath)
            Dim ER As String = DInfo.Name

            Change_Wallpaper(ER)

        Catch ex As Exception

            If System.IO.Directory.Exists(TFPath) = True Then

                Change_Wallpaper(TFPath)

            Else

                MsgBox("Error: Directory " & TFPath & " doesn't exist!", MsgBoxStyle.Critical, "Error")

            End If

        End Try

    End Sub

    Private Sub Change_Wallpaper(ByVal Path As String)

        Dim TStor As String()

        TStor = System.IO.Directory.GetFiles(Path, "*.*")

        For Each hold As String In TStor

            Pics.Add(hold)

        Next

        Pics.Sort()

        Microsoft.Win32.Registry.SetValue("HKEY_CURRENT_USER\Control_ Panel\Desktop", "WallpaperStyle", 3, Microsoft.Win32.RegistryValueKind.String)

        My.Settings.WeAreOn = 1

        SystemParametersInfo(20, 3, Pics(0), &H1)

    End Sub

    Private Sub Next_wallpaper()

        If My.Settings.WeAreOn >= Pics.Count Then

            My.Settings.WeAreOn = 0
            SystemParametersInfo(20, 0, Pics(My.Settings.WeAreOn), &H1)

        Else

            SystemParametersInfo(20, 0, Pics(My.Settings.WeAreOn), &H1)

        End If

        My.Settings.WeAreOn += 1

    End Sub


    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick

        If Pics.Count <> 0 Then

            Next_wallpaper()

        End If

    End Sub

    Private Sub TimeUnit_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TimeUnit.SelectedIndexChanged

        Dim FinalTime As Integer = 0

        If TimeUnit.SelectedItem = "Minutes" Then

            FinalTime = (60 * TimeInt.Text) * 1000

            Timer1.Stop()
            Timer1.Interval = FinalTime
            Timer1.Start()

        ElseIf TimeUnit.SelectedItem = "Seconds" Then

            FinalTime = TimeInt.Text * 1000

            Timer1.Stop()
            Timer1.Interval = FinalTime
            Timer1.Start()

        ElseIf TimeUnit.SelectedItem = "Hours" Then

            FinalTime = ((60 * 60) * TimeInt.Text) * 1000

            Timer1.Stop()
            Timer1.Interval = FinalTime
            Timer1.Start()

        End If

    End Sub

    Private Sub TimeInt_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TimeInt.TextChanged

        Dim FinalTime As Integer = 0

        If TimeUnit.SelectedItem = "Minutes" Then

            FinalTime = (60 * TimeInt.Text) * 1000

            Timer1.Stop()
            Timer1.Interval = FinalTime
            Timer1.Start()

        ElseIf TimeUnit.SelectedItem = "Seconds" Then

            FinalTime = TimeInt.Text * 1000

            Timer1.Stop()
            Timer1.Interval = FinalTime
            Timer1.Start()

        ElseIf TimeUnit.SelectedItem = "Hours" Then

            FinalTime = ((60 * 60) * TimeInt.Text) * 1000

            Timer1.Stop()
            Timer1.Interval = FinalTime
            Timer1.Start()

        End If

    End Sub
End Class

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This line was what I hacked together for center:

Code:

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        Microsoft.Win32.Registry.SetValue("HKEY_CURRENT_USER\Control_ Panel\Desktop", "WallpaperStyle", 3, Microsoft.Win32.RegistryValueKind.String)

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You can use the FileWatcher() class, which fires when a folder changes.

Also, one screen is added to the other, so try adding the width's

Okay, so how do i get the width's of the two screens?

You'd need a few API's, I think.

http://www.codeproject.com/KB/system...lemonitor.aspx

So will this allow me to center the pictures based on both screen's resolution? I've seen things that do it. Also, how do I even go about centering the desktop background in code? I've tried the registry but that didn't work at all.

Strange problem. so i found some code and actually got it to work good, but now I have another small problem. It works in so much as it will set the registry value, but the desktop won't update itself to reflect that new value unless i go to background settings. When I do that, it automatically adjusts itself to be whatever value I put in, such as 2 for fit to screen. how can i update the desktop to reflect the new value through vb.net?

Code:

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Imports System
Imports System.Runtime.InteropServices
Imports Microsoft.Win32

Public Class Form1

    <DllImport("user32.dll", CharSet:=CharSet.Auto)> _
    Private Shared Function SystemParametersInfo(ByVal uAction As Integer, ByVal uParam As Integer, ByVal lpvParam As String, ByVal fuWinIni As Integer) As Integer
    End Function

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

        SystemParametersInfo(20, 0, "C:\users\cooper\pictures\backgrounds\3.jpg", 1 Or 2)

        Dim rkWallPaper As RegistryKey = Registry.CurrentUser.OpenSubKey("Control Panel\Desktop", True)
        rkWallPaper.SetValue("WallpaperStyle", 2, RegistryValueKind.String)
        rkWallPaper.SetValue("TileWallpaper", 0, RegistryValueKind.String)
        rkWallPaper.Close()

    End Sub
End Class

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The problem is that you call SystemparametersInfo before editing the registry, rather have it that SystemparametersInfo is called after the modifications to the registry. I'm actually surprised that you did get a picture, because as I recall, systemparametersInfo only works with bmp images.

Will the paper always be centered ¿ As you have finally realised, you need 2 settings ( WallpaperStyle and TileWallpaper ) - to allow for the other settings, you can do :

Code:

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        Select Case WPStyle 'What Style Was Chosen ¿
            Case 1 'Tile
                WallStyleReg.SetValue("TileWallpaper", "1")
                WallStyleReg.SetValue("WallpaperStyle", "0")

            Case 2 'Center
                WallStyleReg.SetValue("TileWallpaper", "0")
                WallStyleReg.SetValue("WallpaperStyle", "0")

            Case 3 'Stretch
                WallStyleReg.SetValue("TileWallpaper", "0")
                WallStyleReg.SetValue("WallpaperStyle", "2")
        End Select

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I've also sometimes encountered a problem where the wallpaper didn't apply immediately, so you may need to call SystemParametersInfo twice.

How to do all these, is explained in this article :
http://www.codeguru.com/vb/gen/vb_mi...le.php/c14139/

It is in VB.NET 2003 though, but still compatibel with the newer versions :)

For dual monitors, have a look here :
http://www.codeguru.com/forum/showth...t=dual+monitor

and
http://blogs.msdn.com/coding4fun/arc...2/5246528.aspx