[jacobjordan]

Almost ready to give up. Here's the deal, i have about a mile of code in my whole project, so i will try to cut it down as much a possible. I am making a virtual desktop program. The program stores the desktops in an array, so it can have an unlimited amount. I have been testing this with 2 desktops, just to get it working. Guess what, it wont!! Ok, i will try to explain my code in a nutshell here:

My project consists of 2 programs and a dll called VDesk. One program runs all the time and references the dll, and tells the dll to switch the desktop on a hotkey. I will not show any of that code, because all it does it tell the desktops to switch, and i am having no problem with it. In the dll: i have 4 objects: A structure called Window that represents an open window on a desktop. A class called Methods, all that holds is declares on windows dll's, and it is used by all of the rest of my code. A class called Desktop. Basically all that holds is a Collection(Of Window) and a property called name, which is the string name to represent the desktop. Lastly, and most importantly, i have a class called VirtualDesktopManager. It holds a Collection(Of Desktop) and several overloads of a method called SwitchDesktop, which switches between desktops. In the other program: it is called DeskSwitch.exe. I has one form called Switcher. I will explain more about that later on.

Now for my code. Here is the code for the Methods class, which i believe is the easiest to figure out:

Imports System.Runtime.InteropServices
Public Class Methods
    ''' <summary>
    ''' Determines weather or not a handle is a window
    ''' </summary>
    ''' <param name="hWnd">The hande to the process</param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Declare Function IsWindow Lib "user32.dll" (ByVal hWnd As IntPtr) As Boolean
    Public Delegate Function CallBack(ByVal hwnd As IntPtr, ByVal lParam As Integer) As Boolean
    ''' <summary>
    ''' Enumarates through all the open windows
    ''' </summary>
    ''' <param name="Adress">A method</param>
    ''' <param name="y">Must be zero</param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Declare Function EnumWindows Lib "user32" (ByVal Adress As CallBack, ByVal y As Integer) As Integer
    ''' <summary>
    ''' Determines if a window is shown in the taksbar
    ''' </summary>
    ''' <param name="hwnd">The handle to the window</param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Declare Function IsWindowVisible Lib "user32.dll" (ByVal hwnd As IntPtr) As Boolean
    ''' <summary>
    ''' Returns the handle to the foreground window
    ''' </summary>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Declare Function GetForegroundWindow Lib "user32.dll" () As IntPtr
    ''' <summary>
    ''' Ends a process
    ''' </summary>
    ''' <param name="hWnd">The handle to the window to kill</param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Declare Function EndTask Lib "user32.dll" (ByVal hWnd As IntPtr) As Integer
    ''' <summary>
    ''' Shows or hides a window
    ''' </summary>
    ''' <param name="hwnd">The handle to the window</param>
    ''' <param name="nCmdShow"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Declare Function ShowWindow Lib "user32.dll" (ByVal hwnd As IntPtr, ByVal nCmdShow As WindowShowStyle) As Boolean
    Public Enum WindowShowStyle As UInteger
        ''' <summary>Hides the window and activates another window.</summary>
        ''' <remarks>See SW_HIDE</remarks>
        Hide = 0
        '''<summary>Activates and displays a window. If the window is minimized
        ''' or maximized, the system restores it to its original size and
        ''' position. An application should specify this flag when displaying
        ''' the window for the first time.</summary>
        ''' <remarks>See SW_SHOWNORMAL</remarks>
        ShowNormal = 1
        ''' <summary>Activates the window and displays it as a minimized window.</summary>
        ''' <remarks>See SW_SHOWMINIMIZED</remarks>
        ShowMinimized = 2
        ''' <summary>Activates the window and displays it as a maximized window.</summary>
        ''' <remarks>See SW_SHOWMAXIMIZED</remarks>
        ShowMaximized = 3
        ''' <summary>Maximizes the specified window.</summary>
        ''' <remarks>See SW_MAXIMIZE</remarks>
        Maximize = 3
        ''' <summary>Displays a window in its most recent size and position.
        ''' This value is similar to "ShowNormal", except the window is not
        ''' actived.</summary>
        ''' <remarks>See SW_SHOWNOACTIVATE</remarks>
        ShowNormalNoActivate = 4
        ''' <summary>Activates the window and displays it in its current size
        ''' and position.</summary>
        ''' <remarks>See SW_SHOW</remarks>
        Show = 5
        ''' <summary>Minimizes the specified window and activates the next
        ''' top-level window in the Z order.</summary>
        ''' <remarks>See SW_MINIMIZE</remarks>
        Minimize = 6
        '''   <summary>Displays the window as a minimized window. This value is
        '''   similar to "ShowMinimized", except the window is not activated.</summary>
        ''' <remarks>See SW_SHOWMINNOACTIVE</remarks>
        ShowMinNoActivate = 7
        ''' <summary>Displays the window in its current size and position. This
        ''' value is similar to "Show", except the window is not activated.</summary>
        ''' <remarks>See SW_SHOWNA</remarks>
        ShowNoActivate = 8
        ''' <summary>Activates and displays the window. If the window is
        ''' minimized or maximized, the system restores it to its original size
        ''' and position. An application should specify this flag when restoring
        ''' a minimized window.</summary>
        ''' <remarks>See SW_RESTORE</remarks>
        Restore = 9
        ''' <summary>Sets the show state based on the SW_ value specified in the
        ''' STARTUPINFO structure passed to the CreateProcess function by the
        ''' program that started the application.</summary>
        ''' <remarks>See SW_SHOWDEFAULT</remarks>
        ShowDefault = 10
        ''' <summary>Windows 2000/XP: Minimizes a window, even if the thread
        ''' that owns the window is hung. This flag should only be used when
        ''' minimizing windows from a different thread.</summary>
        ''' <remarks>See SW_FORCEMINIMIZE</remarks>
        ForceMinimized = 11

    End Enum
    <Runtime.InteropServices.DllImport("user32.dll")> _
Shared Function GetWindowText(ByVal hWnd As IntPtr, ByVal lpWindowText As System.Text.StringBuilder, _
ByVal nMaxCount As Integer) As Integer
    End Function

    ''' <summary>
    ''' Get's the handle and text of the foreground window
    ''' </summary>
    Public Shared Function GetWindowText(ByVal hwnd As IntPtr) As String
        Dim title As New System.Text.StringBuilder(255)
        Dim titleLength As Integer = GetWindowText(hwnd, title, title.Capacity + 1)
        title.Length = titleLength
        Return title.ToString()
    End Function

    ''' <summary>
    ''' Sets the text of a window
    ''' </summary>
    ''' <param name="hWnd">The handle to the window</param>
    ''' <param name="lpstring">The text to set</param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Declare Auto Function SetWindowText Lib "user32.dll" (ByVal hWnd As IntPtr, ByVal lpstring As String) As Boolean
End Class

As you can see, all that holds is methods that are inside windows dll's that my project needs to function.

Here, i have the code for the Window structure:

Imports VDesk.Methods
''' <summary>
''' Represents an open, visible window
''' </summary>
Public Structure Window
    ''' <summary>
    ''' Creates a new window based on the specified handle
    ''' </summary>
    ''' <param name="hwnd">The handle to the window</param>
    Sub New(ByVal hwnd As IntPtr)
        Me.hwnd = hwnd
        Me.mainwintext = GetWindowText(Handle)
    End Sub
    ''' <summary>
    ''' Gets the handle of the window
    ''' </summary>
    Public ReadOnly Property Handle() As IntPtr
        Get
            Return hwnd
        End Get
    End Property
    ''' <summary>
    ''' Gets or sets the text of the window
    ''' </summary>
    Public Property Text() As String
        Get
            Return mainwintext
        End Get
        Set(ByVal value As String)
            SetWindowText(hwnd, value)
            mainwintext = value
        End Set
    End Property
    Private hwnd As IntPtr
    Private mainwintext As String
    ''' <summary>
    ''' Shows the window in it's last size and position after being hidden
    ''' </summary>
    Public Sub Show()
        ShowWindow(Handle, WindowShowStyle.Show)
    End Sub
    ''' <summary>
    ''' Maximizes the window
    ''' </summary>
    Public Sub Maximize()
        ShowWindow(Handle, WindowShowStyle.Maximize)
    End Sub
    ''' <summary>
    ''' Minimizes the window
    ''' </summary>
    Public Sub Minimize()
        ShowWindow(Handle, WindowShowStyle.ShowMinimized)
    End Sub
    ''' <summary>
    ''' Shows the window maximized after being hidden
    ''' </summary>
    Public Sub ShowMaximized()
        ShowWindow(Handle, WindowShowStyle.ShowMaximized)
    End Sub
    ''' <summary>
    ''' Shows the window in it's default startup size after being hidden
    ''' </summary>
    Public Sub ShowDefault()
        ShowWindow(Handle, WindowShowStyle.ShowDefault)
    End Sub
    ''' <summary>
    ''' Shows the window in it's after being hidden.
    ''' </summary>
    Public Sub ShowNormal()
        ShowWindow(Handle, WindowShowStyle.ShowNormal)
    End Sub
    Public Sub Kill()
        EndTask(Handle)
    End Sub
    Public Sub Hide()
        ShowWindow(Handle, WindowShowStyle.Hide)
    End Sub
    Public Sub Restore()
        ShowWindow(Handle, WindowShowStyle.Restore)
    End Sub
    Public Function HasExited() As Boolean
        Return Not IsWindow(Handle)
    End Function
End Structure

That basically holds the handle and several methods that can be applied to an open window.

Here is the Desktop class:

''' <summary>
''' Represents a desktop that controls a set of windows
''' </summary>
Public Class Desktop
    ''' <summary>
    ''' Creates a new desktop object
    ''' </summary>
    ''' <param name="Name">The name of the desktop</param>
    Public Sub New(ByVal Name As String)
        DesktopName = Name
    End Sub
    ''' <summary>
    ''' Represents the windows displayed on the desktop
    ''' </summary>
    Public Windows As New System.Collections.ObjectModel.Collection(Of Window)
    ''' <summary>
    ''' Represents the name of the desktop
    ''' </summary>
    Public DesktopName As String
End Class

Not much there. All that does is hold a collection of windows and a name property.

Here is the code i am having trouble with

Ok, i had to show you that code so you wouldn't be lost when i showed you this. First, i am going to show you two classes. One is called VirtualDesktopManager. It basically holds a collection of desktops, properties that will return the current desktop, and methods to switch them. Next, i have a separate program called DeskSwitch.exe with a form called Switcher. It is what actually switches the desktop. Here's how they work together: The VirtualDesktopManager class, when called to switch between desktops, will create a file called Desktop.dat, in which it will write the handles and text of the windows that need to be shown on the new desktop. It then shells a program called DeskSwitcher.exe, and passes it the path to the dat file. When the DeskSwitch.exe runs, it will show it's form maximized, and fade the screen black via a timer (just to make it look better). After that is done, it will hide all the open windows, and open the dat file and show all the windows specified in that file. It will then fade transparent again via another timer, delete the dat file, and close. I know my problem is in one of these classes, i just have no idea which one.

First, here is the code for the VirtualDesktopManager class:

Imports VDesk.Methods
Public Class VirtualDesktopManager
    Public Sub New()
        curdeskind = 0
        UpdateActiveWindowList()
    End Sub

    Public Sub New(ByVal Desks As Collections.ObjectModel.Collection(Of Desktop))
        Desktops = Desks
        curdeskind = 0
        UpdateActiveWindowList()
    End Sub

    Private ActiveWindows As New System.Collections.ObjectModel.Collection(Of Window)
    ''' <summary>
    ''' Represents the collection of dekstops handled by this manager
    ''' </summary>
    ''' <remarks></remarks>
    Public Desktops As New System.Collections.ObjectModel.Collection(Of Desktop)

    'This is the current desktop name
    Public ReadOnly Property CurrentDesktopName() As String
        Get
            Return curdesk.DesktopName
        End Get
    End Property
    ' This is the current desktop index
    Public ReadOnly Property CurrentDesktopIndex() As Integer
        Get
            Return curdeskind
        End Get
    End Property
    ' This is the current desktop
    Public ReadOnly Property CurrentDesktop() As Desktop
        Get
            Return curdesk
        End Get
    End Property

    Private curdesk As Desktop
    Private curdeskind As Integer
    Private Sub UpdateActiveWindowList()
        ActiveWindows.Clear()
        EnumWindows(AddressOf Enumer, 0)
    End Sub

    Private Function Enumer(ByVal hwnd As IntPtr, ByVal lParam As Integer) As Boolean
        If IsWindowVisible(hwnd) And Not GetWindowText(hwnd) = "" And Not GetWindowText(hwnd) = "Program Manager" Then
            ActiveWindows.Add(New Window(hwnd))
        End If
        Return True
    End Function

    Public tdir As String 'Represents the current directory
    Public Sub SwitchDesk(ByVal Index As Integer)
        If Desktops.Count - 1 > Index Then Throw New ArgumentOutOfRangeException( _
        "Index was out of the bounds of the Desktops collection")
        SaveCurrentDesktopLayout()
        FileOpen(1, tdir & "\Desktop.dat", OpenMode.Output)
        For Each win As Window In Desktops(Index).Windows
            WriteLine(1, win.Handle.ToInt32)
            WriteLine(1, win.Text.ToCharArray())
        Next
        FileClose(1)
        curdeskind = Index
        curdesk = Desktops(Index)
        Shell(Chr(34) & tdir & "\DeskSwitch.exe" & Chr(34) & " " & Chr(34) & tdir & "\Desktop.dat" & Chr(34))
    End Sub

    ''' <summary>
    ''' Saves the current layout of the desktop to the active desktop object. This method is called
    ''' automatically every time the SwitchDesk() method is called.
    ''' </summary>
    ''' <remarks></remarks>
    Public Sub SaveCurrentDesktopLayout()
        UpdateActiveWindowList()
        Desktops(curdeskind).Windows = ActiveWindows
    End Sub

    Public Sub SwitchDesk(ByVal Destination As Desktop)
        If Not Desktops.Contains(Destination) Then Throw New ArgumentException( _
        "The requested desktop is not contained in the Desktops collection")
        SaveCurrentDesktopLayout()
        FileOpen(1, tdir & "\Desktop.dat", OpenMode.Output)
        For Each win As Window In Destination.Windows
            WriteLine(1, win.Handle)
            WriteLine(1, win.Text.ToCharArray())
        Next
        FileClose(1)
        curdeskind = Desktops.IndexOf(Destination)
        curdesk = Destination
        Shell(Chr(34) & tdir & "\DeskSwitch.exe" & Chr(34) & " " & Chr(34) & tdir & "\Desktop.dat" & Chr(34))
    End Sub

    Public Sub SwitchDesk(ByVal DestinationName As String)
        Dim ind As Integer
        For Each d As Desktop In Desktops
            If d.DesktopName = DestinationName Then
                ind = Desktops.IndexOf(d)
                GoTo switch
            End If
        Next
        Throw New ArgumentException( _
       "No desktop in the desktop collection has a name with the one you specified")
switch:
        SaveCurrentDesktopLayout()
        FileOpen(1, tdir & "\Desktop.dat", OpenMode.Output)
        For Each win As Window In Desktops(ind).Windows
            WriteLine(1, win.Handle.ToInt32)
            WriteLine(1, win.Text.ToCharArray())
        Next
        FileClose(1)
        curdeskind = ind
        curdesk = Desktops(ind)
        Shell(Chr(34) & tdir & "\DeskSwitch.exe" & Chr(34) & " " & Chr(34) & tdir & "\Desktop.dat" & Chr(34))
    End Sub
End Class

And here is the code for the Switcher form:

Imports VDesk
Imports VDesk.Methods
Public Class Switcher
    Private ActiveWindows As New System.Collections.ObjectModel.Collection(Of Window)
    Private Sub HideScreen_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles HideScreen.Tick
        Me.Opacity += 0.1
        If Me.Opacity = 1 Then
            HideScreen.Enabled = False
            switch()
        End If
    End Sub

    Private Sub ShowScreen_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ShowScreen.Tick
        Me.Opacity -= 0.1
        If Me.Opacity = 0 Then
            ShowScreen.Enabled = False
            Application.Exit()
        End If
    End Sub

    Public Sub UpdateActiveWindowList()
        ActiveWindows.Clear()
        EnumWindows(AddressOf Enumer, 0)
    End Sub

    Function Enumer(ByVal hwnd As IntPtr, ByVal lParam As Integer) As Boolean
        If IsWindowVisible(hwnd) And Not GetWindowText(hwnd) = "" And Not GetWindowText(hwnd) = "Program Manager" Then
            ActiveWindows.Add(New Window(hwnd))
        End If
        Return True
    End Function

    <Runtime.InteropServices.DllImport("user32.dll")> _
    Shared Function SetForegroundWindow(ByVal hwnd As IntPtr) As Long
    End Function

    Dim desk As Integer = 1
    Private Sub switch()
        UpdateActiveWindowList()
        SetForegroundWindow(Process.GetProcessesByName("explorer")(0).MainWindowHandle)
        For Each win As Window In ActiveWindows
            My.Computer.Audio.Play(My.Computer.FileSystem.CurrentDirectory & "\Sounds\Notify.wav", AudioPlayMode.WaitToComplete)
            win.Hide()
        Next
        Dim wins As New Collections.ObjectModel.Collection(Of InactiveWindow)
        FileOpen(1, Args.arg, OpenMode.Input)
        Do Until EOF(1)
            Dim h As IntPtr = LineInput(1)
            Dim t As String = LineInput(1)
            Dim w As New InactiveWindow(h, t)
            w.Handle = h
            w.Text = t
            wins.Add(w)
            My.Computer.Audio.Play(My.Computer.FileSystem.CurrentDirectory & "\Sounds\Notify.wav", AudioPlayMode.WaitToComplete)
        Loop
        For Each win As InactiveWindow In wins
            win.Show()
            My.Computer.Audio.Play(My.Computer.FileSystem.CurrentDirectory & "\Sounds\Notify.wav", AudioPlayMode.WaitToComplete)
        Next
        FileClose(1)
        IO.File.Delete(Args.arg)
        ShowScreen.Enabled = True
    End Sub

    Private Sub VirtualDesktopManager_Shown(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Shown
        HideScreen.Enabled = True
    End Sub
End Class

If you have even read this far, i give you high marks for even taking the time to do that. If you have done something like this before, i would love to know how you did it, or any suggestions you have for me. Also note there may of been some unused code in my project. I have changed it up so many times it may have gotten a bit unorganized.

The problem is: like i said, i am testing this with 2 desktops. When the program starts, it saves the layout of the screen into the first desktop. When i tell it to switch to the second, it does that fine. The desktop is blank, like it should be because i havn't opened any windows on it. But, when i switch back to the first, none of the windows i had open there are visible either! After that, it screws up in so many ways i can't even keep track of them.

This post has been edited by jacobjordan: 10 July 2008 - 12:29 PM

[AdamSpeight2008]

After all that you never stated what your problem is?

[jacobjordan]

Oh. So much there i knew i forgot something. The problem is: like i said, i am testing this with 2 desktops. When the program starts, it saves the layout of the screen into the first desktop. When i tell it to switch to the second, it does that fine. The desktop is blank, like it should be because i havn't opened any windows on it. But, when i switch back to the first, none of the windows i had open there are visible either! After that, it screws up in so many ways i can't even keep track of them.

[AdamSpeight2008]

Are you save all the desktop layouts or just one, the one being switch from?

[jacobjordan]

When i tell it to switch the desktop, the VirtualDesktopManager saves all of the active windows into an array called ActiveWindows. It then takes the Windows of the active desktop and updates it with the ActiveWindows array. Then, it accesses the array of windows that were last on the desktop that the user is requesting to switch to, and saves it to a file. It runs the Switcher program, and it hides all the open windows and shows the windows in the file.

Also, i have managed to figure out that the problem is in the VirtualDesktopManager class, and not the switcher program. I am still clueless on what the problem is, however.

[AdamSpeight2008]

jacobjordan, on 10 Jul, 2008 - 08:50 PM, said:

When i tell it to switch the desktop, the VirtualDesktopManager saves all of the active windows into an array called ActiveWindows. It then takes the Windows of the active desktop and updates it with the ActiveWindows array. Then, it accesses the array of windows that were last on the desktop that the user is requesting to switch to, and saves it to a file. It runs the Switcher program, and it hides all the open windows and shows the windows in the file.

Also, i have managed to figure out that the problem is in the VirtualDesktopManager class, and not the switcher program. I am still clueless on what the problem is, however.

Why is there two SwitchDesk in VirtualDesktopManager ?

[jacobjordan]

Ok, i don't think you quite understand.

I have 3 items in my project: One program runs all the time. It refrences the dll where VirtualDesktopManager is located. It has a global variable that looks like

Dim DeskMan As New VDesk.VirtualDesktopManager()

And when a hotkey is pressed to go to another desktop, it invokes the method:

DeskMan.SwitchDesk(SomeDesktop)

Now, all the VirtualDesktopManager does, is store the desktops and their layout. When the SwitchDesk method is called, it runs a program called DeskSwitch.exe which contains the actual methods that will switch the desktop. I put that in another program to save computer memory.

[jacobjordan]

OK: Another question here
I think i may of figured out what is happening!!

If i had two Collection(Of T)'s, and i filled collection1 with items, and i put this code

collection2 = colection1

And then, after that i removed everything from collection1 with the clear method, would that also clear collection2????

[AdamSpeight2008]

jacobjordan, on 10 Jul, 2008 - 09:29 PM, said:

OK: Another question here
I think i may of figured out what is happening!!

If i had two Collection(Of T)'s, and i filled collection1 with items, and i put this code

collection2 = colection1

And then, after that i removed everything from collection1 with the clear method, would that also clear collection2????

The above line sets Collection2 as a reference of collection1.

[jacobjordan]

So, in other words, yes??

[AdamSpeight2008]

yes

collection2.clear
collection2.addrange(collection1.tolist)

Is what you need.

[jacobjordan]

Then that's my problem. I could spend an hour or so explaining exactly what i was doing wrong in this post, but unless somebody begs me to, i think i will just sit here in my chair smiling because i finally got this solved after about a week!!

This post has been edited by jacobjordan: 10 July 2008 - 01:43 PM

[AdamSpeight2008]

jacobjordan, on 10 Jul, 2008 - 09:43 PM, said:

Then that's my problem. I could spend an hour or so explaining exactly what i was doing wrong in this post, but unless somebody begs me to, i think i will just sit here in my chair smiling because i finally got this solved after about a week!!

Don't worry I've made this error as well and it stumped me.

[jacobjordan]

Well, i fixed my problem and got it working (for the most part). I still have a few minor bugs, but i can get those worked out by days end. Thanks for all the help Adam!