[jbullard]

Tutorial: Creating a desktop band object
Language: VB.Net 03, 05
Level: Advanced


Step 1: The very first thing that we must do when creating a deskband object is to get some API stuff out of the way. Below is a list of API commands and there enum/structures.

Lets put all of the following in a module named modSidebar.vb.

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Module modSidebar


SHAppBarMessage
- Used to send a message to register a bar

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    Public Declare Function SHAppBarMessage Lib "shell32.dll" Alias _
                            "SHAppBarMessage" ( _
                            ByVal dwMessage As Integer, _
                            ByRef pData As APPBARDATA) As System.UInt32


MoveWindow
- Used to move windows or placement on desktop

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    Public Declare Function MoveWindow Lib "User32.dll" Alias _
                            "MoveWindow" ( _
                            ByVal hWnd As IntPtr, _
                            ByVal x As Integer, _
                            ByVal y As Integer, _
                            ByVal cx As Integer, _
                            ByVal cy As Integer, _
                            ByVal repaint As Boolean) As Boolean


RegisterWindow
- Used to register a window with Windows

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    Public Declare Auto Function RegisterWindowMessage Lib _
                            "User32.dll" ( _
                            ByVal msg As String) As Integer


FindWindow
- Used to find a window that has been registered

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    Public Declare Function FindWindowA Lib "user32" ( _
                            ByVal lpClassName As String, _
                            ByVal lpWindowName As String) As Long


SetWindowPos
- Used to set the position of the registered window

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    Public Declare Function SetWindowPos Lib "user32" ( _
                            ByVal hwnd As Integer, _
                            ByVal hWndInsertAfter As Integer, _
                            ByVal x As Integer, _
                            ByVal y As Integer, _
                            ByVal cx As Integer, _
                            ByVal cy As Integer, _
                            ByVal wFlags As Integer) As Integer


And now lets define our structures.

APPBARDATA
- This is where the information for the bar is created/stored

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    Structure APPBARDATA
        Public cbSize As Integer
        Public hWnd As IntPtr
        Public uCallbackMessage As Integer
        Public uEdge As Integer
        Public rc As RECT
        Public lParam As IntPtr
    End Structure


RECT
- This is basically a structure for drawing

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    Structure RECT
        Public left As Integer
        Public top As Integer
        Public right As Integer
        Public bottom As Integer
    End Structure


Now lets move on to enumerations.

ABMsg
- This is used to send a specific message on what type of bar we want.

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    Enum ABMsg
        ABM_NEW = 0
        ABM_REMOVE = 1
        ABM_QUERYPOS = 2
        ABM_SETPOS = 3
        ABM_GETSTATE = 4
        ABM_GETTASKBARPOS = 5
        ABM_ACTIVATE = 6
        ABM_GETAUTOHIDEBAR = 7
        ABM_SETAUTOHIDEBAR = 8
        ABM_WINDOWPOSCHANGED = 9
        ABM_SETSTATE = 10
    End Enum


ABNotify
- Used to send a message to a window

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    Enum ABNotify
        ABN_STATECHANGE = 0
        ABN_POSCHANGED = 1
        ABN_FULLSCREENAPP = 2
        ABN_WINDOWARRANGE = 3
    End Enum


ABEdge
- This is used to say where we want the bar docked

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    Enum ABEdge
        ABE_LEFT = 0
        ABE_TOP = 1
        ABE_RIGHT = 2
        ABE_BOTTOM = 3
    End Enum


Now lets setup some variables

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    Public fBarRegistered As Boolean = False
    Public uCallBack As Integer


Now end the module.

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End Module


Note: The rest of this information goes into Form1 or whatever your main form name is called. Also, you need to import the following.

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Imports System.Runtime.InteropServices


Step 2: Now that we have our module setup we need to go into our main form and do some extra steps to make sure that we are able to receive window messages.

So the first thing we are going to do here is to do whats called subclassing. Here we are going to subclass window messages with a function called WndProc.

WndProc
- Used to catch window messages

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    Protected Overloads Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
        If m.Msg = uCallBack Then
            Select Case m.WParam.ToInt32
                Case CType(ABNotify.ABN_POSCHANGED, Integer)
                    ABSetPos()
                    ' break
            End Select
        End If
        Try
            MyBase.WndProc(m)
        Catch ex As Exception
            '
        End Try
    End Sub


Step 3: After we have our message function setup we now need to create a param option for making sure our form is displayed properly.

CreateParams
- Used to setup the display of our form.

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    Protected Overloads Overrides ReadOnly Property CreateParams() As System.Windows.Forms.CreateParams
        Get
            Dim cp As CreateParams = MyBase.CreateParams
            cp.Style = cp.Style And ((Not 12582912))
            cp.Style = cp.Style And ((Not 8388608))
            cp.ExStyle = 128 Or 8
            Return cp
        End Get
    End Property


Step 4: Okay. Now that we have those setup next we need to get into the nitty gritty of our code. The next sub procedure we are going to make is ABSetPos which actually does all of the work for us.

ABSetPos
- Docks/Registers our bar

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    Private Sub ABSetPos()
        Dim abd As APPBARDATA = New APPBARDATA
        abd.cbSize = Marshal.SizeOf(abd)
        abd.hWnd = Me.Handle
        abd.uEdge = CType(ABEdge.ABE_TOP, Integer)
        If abd.uEdge = CType(ABEdge.ABE_LEFT, Integer) OrElse abd.uEdge = CType(ABEdge.ABE_RIGHT, Integer) Then
            abd.rc.top = 0
            abd.rc.bottom = SystemInformation.PrimaryMonitorSize.Height
            If abd.uEdge = CType(ABEdge.ABE_LEFT, Integer) Then
                abd.rc.left = 0
                abd.rc.right = Size.Width
            Else
                abd.rc.right = SystemInformation.PrimaryMonitorSize.Width
                abd.rc.left = abd.rc.right - Size.Width
            End If
        Else
            abd.rc.left = 0
            abd.rc.right = SystemInformation.PrimaryMonitorSize.Width
            If abd.uEdge = CType(ABEdge.ABE_TOP, Integer) Then
                abd.rc.top = 0
                abd.rc.bottom = Size.Height
            Else
                abd.rc.bottom = SystemInformation.PrimaryMonitorSize.Height
                abd.rc.top = abd.rc.bottom - Size.Height
            End If
        End If
        SHAppBarMessage(CType(ABMsg.ABM_QUERYPOS, Integer), abd)
        Select Case abd.uEdge
            Case CType(ABEdge.ABE_LEFT, Integer)
                abd.rc.right = abd.rc.left + Size.Width
                ' break
            Case CType(ABEdge.ABE_RIGHT, Integer)
                abd.rc.left = abd.rc.right - Size.Width
                ' break
            Case CType(ABEdge.ABE_TOP, Integer)
                abd.rc.bottom = abd.rc.top + Size.Height
                ' break
            Case CType(ABEdge.ABE_BOTTOM, Integer)
                abd.rc.top = abd.rc.bottom - Size.Height
                ' break
        End Select
        SHAppBarMessage(CType(ABMsg.ABM_SETPOS, Integer), abd)
        MoveWindow(abd.hWnd, abd.rc.left, abd.rc.top, abd.rc.right - abd.rc.left, abd.rc.bottom - abd.rc.top, True)
    End Sub


Step 5: Now that we have our main code we need to setup a procedure for checking to see if our bar is registered or not. To do this we simply create another sub procedure. RegisterBar simply does the work for us to see if the bar needs to be registered or unregistered.

Registerbar
- Used to register/unregister our bar

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    Private Sub RegisterBar()
        Dim abd As APPBARDATA = New APPBARDATA
        abd.cbSize = Marshal.SizeOf(abd)
        abd.hWnd = Me.Handle
        If Not fBarRegistered Then
            uCallBack = RegisterWindowMessage("MyDesktopBar")
            abd.uCallbackMessage = uCallBack
            Dim ret As System.UInt32 = SHAppBarMessage(CType(ABMsg.ABM_NEW, Integer), abd)
            fBarRegistered = True
            ABSetPos()
        Else
            SHAppBarMessage(CType(ABMsg.ABM_REMOVE, Integer), abd)
            fBarRegistered = False
        End If
    End Sub


Step 6: So now you are done coding the features and now we can put them to use. To do this we simply call registerbar() in our form load event and registerbar() again in our button close event.

So on your form go a head and create a button. Doesn't matter the name but for this reason I am going to leave it Button1.

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    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        RegisterBar()
        Me.Close()
    End Sub


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


Now you are done.


Run your application and watch it register.


Well, if you have any problems with this or would actually like a breakdown of something that you found here please just post here and I will reply. And as always Happy Coding.

Jason

[iXclusiv]

Hi,

ehm how the hell i get my form to the taskbar like mediplayer in minimized form?

Would be great if you can give me help to set this up.

Greez,

Benny (Regards from germany)

[jbullard]

Benny,

Let me do some research on this. I remember an option to add it but I really can't remember what it was.

Jason

[jbullard]

Benny,

Code Project has a very good example on how to accomplish this. It is pretty straightforward and contains comments. If you need help with it let me know.

HTH,
Jason

[iXclusiv]

Hi,

well it's not for VB.NET it's c#/c++ :/ this one here was the only one i found for vb.net.

and c++ isn't that what i have atm on my pc and i learn VB (im newbie but understand fast)

[jbullard]

Well, let me see if I can convert that one from C# to VB. I wrote this in VB a long time ago but have since switched to C#. Just love the structure of the language compared to VB.

[iXclusiv]

Hi,
great, thx a lot

[jbullard]

Just wanted to let you know that I am about done converting it.

[iXclusiv]

Hi,

i already look forward for this "ultimate code", every person i asked said: impossible.. well never give up^^ nothing is impossible xD, im right hu?

again thx, a lot can't wait 'till i can test it myself^^

[jbullard]

Alright. Here it is ported to VB.NET. In order to get the band object to show here is what you will have to do:

1. Open command prompt to the bin location of the project
2. Run regasm DeskObject.dll /codebase
3. Reboot

If this does not work let me know and when I get home tonight I will see what the problem is. I am at work and do not have administrative rights so unfortunately it is not something I can fix here.

Jason