Building Blocks for an On-screen Keyboard

[jmcilhinney]

I'm creating an on-screen keyboard at the moment to be integrated into an application intended for use on touch-screens. I haven't completed it yet and I'm not necessarily going to post the finished product, but here are the building blocks: a form and a button that will not receive focus. Just note that this behaviour applies to the client area of the form only. If the the user clicks the non-client area, i.e. the title bar and border, then the form will take the focus. This behaviour is just like the in-built Windows OSK.

''' <summary>
''' A button control that cannot receive focus.
''' </summary>
Public Class UnselectableButton
    Inherits System.Windows.Forms.Button
 
#Region " Constructors "
 
    ''' <summary>
    ''' Initialises a new instance of the <see cref="UnselectableButton"/> class.
    ''' </summary>
    Public Sub New()
        MyBase.New()
 
        'The button cannot receive focus.
        Me.SetStyle(ControlStyles.Selectable, False)
    End Sub
 
#End Region 'Constructors
 
#Region " Variables "
 
    ''' <summary>
    ''' Corresponds to the MA_NOACTIVATE window process reply.
    ''' </summary>
    Private Shared ReadOnly noActivate As New IntPtr(NativeConstants.MA_NOACTIVATE)
 
#End Region 'Variables
 
#Region " Methods "
 
    ''' <summary>
    ''' Processes Windows messages.
    ''' </summary>
    ''' <remarks>
    ''' Informs Windows not to activate the window when it is clicked with the mouse.  Note that this behaviour applies to the client area of the window only.
    ''' </remarks>
    Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
        MyBase.WndProc(m)
 
        If m.Msg = NativeConstants.WM_MOUSEACTIVATE Then
            'Tell Windows not to activate the window on a mouse click.
            m.Result = noActivate
        End If
    End Sub
 
    Protected Overrides Sub OnClick(ByVal e As System.EventArgs)
        MyBase.OnClick(e)
    End Sub
 
#End Region 'Methods
 
End Class