[SOURCE] Añadir magnetismo a los bordes de una ventana/Form

He estado refactorizando un viejo snippet, el cual es de mis favoritos, por ese motivo lo posteo aquí para hacer una mención especial y no en el apartado de snippets.

Lo que voy a mostrar es la forma más sencilla (copy&paste) para añadir magnetismo a una ventana.

Personalmente considero que todos deberiamos implementar esta funcionalidad en nuestras aplicaciones, ya que es una funcionalidad muy útil para mantener la organizción de las ventanas en la pantalla, cosa que cualquier usuario-final de su aplicación lo sabrá agradecer.

El magnetismo de ventanas consiste en que, al mover la ventana/Form cerca de un borde de la pantalla, la ventana se adhiera a dicho borde.

Nota: Esta funcionalidad estará incluida en la próxima versión de mi API ElektroKit: http://foro.elhacker.net/net/elektrokit_v10_api_de_proposito_general_para_desarrolladores_de_net-t444997.0.html

El siguiente código está escrito en Vb.Net (es suficiente con copiar, pegar y usar) pero se puede compilar en una dll para desarrolladores de código-C#.

La Class tiene dos propiedades importantes de personalización, la primera propiedad es WindowMagnetizer.Threshold, que indica el margen, en píxeles, en el que se debe producir el magnetismo. Yo suelo utilizar un valor de 35 píxeles ya que soy muy basto moviendo el ratón, pero creo que un valor de 20 seria lo apropiado de forma generalizada.

La otra propiedad se llama WindowMagnetizer.AllowOffscreen, que como su propio nombre indica por si mismo, sirve para habilitar o deshabilitar el poder mover la ventana fuera de los límites de la pantalla activa. (he tenido en cuenta la existencia de una pantalla dual).

El uso de esta class es muy, muy sencillo, tanto como esto:

Código

Private magnetizer As New WindowMagnetizer(Me) With
    {
        .Enabled = True,
        .AllowOffscreen = True,
        .Threshold = 30
    }

Código

private WindowMagnetizer magnetizer;
 
private void Form1_Load(object sender, EventArgs e) {
 
   magnetizer = new WindowMagnetizer(this)
                    {
                        Enabled = true,
                        AllowOffscreen = true,
                        Threshold = 30
                    };  
}

Sin más, el código fuente:

Código

' ***********************************************************************
' Author   : Elektro
' Modified : 01-December-2015
' ***********************************************************************
 
#Region " Public Members Summary "
 
#Region " Constructors "
 
' WindowMagnetizer.New(IWin32Window)
 
#End Region
 
#Region " Properties "
 
' WindowMagnetizer.Handle As IntPtr
' WindowMagnetizer.OwnerWindow As IWin32Window
' WindowMagnetizer.Threshold As Integer
' WindowMagnetizer.Enabled As Boolean
' WindowMagnetizer.AllowOffscreen As Boolean
 
#End Region
 
#Region " Methods "
 
' WindowMagnetizer.Dispose()
 
#End Region
 
#End Region
 
#Region " Usage Examples "
 
'Private magnetizer As New WindowMagnetizer(Me) With
'    {
'        .Enabled = True,
'        .AllowOffscreen = True,
'        .Threshold = 30
'    }
 
#End Region
 
#Region " Option Statements "
 
Option Explicit On
Option Strict On
Option Infer Off
 
#End Region
 
#Region " Imports "
 
Imports System
Imports System.ComponentModel
Imports System.Drawing
Imports System.Linq
Imports System.Runtime.InteropServices
Imports System.Windows.Forms
 
' Imports Elektro.Interop.Win32
' Imports Elektro.Interop.Win32.Enums
' Imports Elektro.Interop.Win32.Types
 
#End Region
 
#Region " Window Magnetizer "
 
    ''' ----------------------------------------------------------------------------------------------------
    ''' <summary>
    ''' Add magnetism to the edges of a window,
    ''' in this way, by bringing the window to a screen edge, the edge of the window adheres it to the edge of the screen.
    ''' </summary>
    ''' ----------------------------------------------------------------------------------------------------
    ''' <example> This is a code example.
    ''' <code>
    ''' Private magnetizer As New WindowMagnetizer(Me) With
    '''     {
    '''         .Enabled = True,
    '''         .AllowOffscreen = True,
    '''         .Threshold = 30
    '''     }
    ''' </code>
    ''' </example>
    ''' ----------------------------------------------------------------------------------------------------
    Public Class WindowMagnetizer : Inherits NativeWindow : Implements IDisposable
 
#Region " Private Fields "
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Determines whether the owner window is being resized by one of its edges.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        Protected isResizing As Boolean
 
#End Region
 
#Region " Properties "
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets the window that owns this <see cref="WindowMagnetizer"/> instance.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <value>
        ''' The window.
        ''' </value>
        ''' ----------------------------------------------------------------------------------------------------
        Public Overridable ReadOnly Property OwnerWindow As IWin32Window
            <DebuggerStepThrough>
            Get
                Return Me.ownerWindowB
            End Get
        End Property
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' ( Backing field )
        ''' The window that owns this <see cref="WindowMagnetizer"/> instance.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        Protected ownerWindowB As IWin32Window
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets the handle for the window that owns this <see cref="WindowMagnetizer"/> instance.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <value>
        ''' The handle.
        ''' </value>
        ''' ----------------------------------------------------------------------------------------------------
        Public Overridable Shadows ReadOnly Property Handle As IntPtr
            <DebuggerStepThrough>
            Get
                Return MyBase.Handle
            End Get
        End Property
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets or sets, in pixels, the minimum threshold that the magnetic window needs to dock it on the nearest window border.
        ''' <para></para>
        ''' (Default value is <c>20</c>))
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <value>
        ''' The minimum threshold that the magnetic window needs to dock it on the nearest window border.
        ''' </value>
        ''' ----------------------------------------------------------------------------------------------------
        Public Overridable Property Threshold As Integer
            <DebuggerStepThrough>
            Get
                Return Me.thresholdB
            End Get
            <DebuggerStepThrough>
            Set(ByVal value As Integer)
                Me.thresholdB = value
            End Set
        End Property
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' ( Backing field )
        ''' The minimum threshold that the magnetic window needs to dock it on the nearest window border.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        Protected thresholdB As Integer
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets or sets a value indicating whether the magnetizer is enabled.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <value>
        ''' <see langword="True"/> if the magnetizer is enabled, otherwise, <see langword="False"/>.
        ''' </value>
        ''' ----------------------------------------------------------------------------------------------------
        Public Overridable Property Enabled As Boolean
            <DebuggerStepThrough>
            Get
                Return Me.enabledB
            End Get
            <DebuggerStepThrough>
            Set(ByVal value As Boolean)
                Me.enabledB = value
            End Set
        End Property
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' ( Backing field )
        ''' A value indicating whether the magnetizer is enabled.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        Protected enabledB As Boolean
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets or sets a value indicating whether the window can be moved off-screen.
        ''' <para></para>
        ''' Default value is <see langword="True"/>.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <value>
        ''' <see langword="True"/> if the window can be moved off-screen, otherwise, <see langword="False"/>.
        ''' </value>
        ''' ----------------------------------------------------------------------------------------------------
        Public Overridable Property AllowOffscreen As Boolean
            <DebuggerStepThrough>
            Get
                Return Me.allowOffscreenB
            End Get
            <DebuggerStepThrough>
            Set(ByVal value As Boolean)
                Me.allowOffscreenB = value
            End Set
        End Property
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' ( Backing field )
        ''' A value indicating whether the window can be moved off-screen.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        Protected allowOffscreenB As Boolean
 
#End Region
 
#Region " Constructors "
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Prevents a default instance of the <see cref="WindowMagnetizer"/> class from being created.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        <DebuggerNonUserCode>
        Private Sub New()
        End Sub
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Initializes a new instance of the <see cref="WindowMagnetizer"/> class.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="window">
        ''' The <see cref="IWin32Window"/> window that owns this instance (eg. a <see cref="Form"/> window).
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        <DebuggerStepThrough>
        Public Sub New(ByVal window As IWin32Window)
 
            Me.allowOffscreenB = True
            Me.thresholdB = 20
            Me.ownerWindowB = window
 
            MyBase.AssignHandle(window.Handle)
 
        End Sub
 
#End Region
 
#Region " Private Methods "
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' If the margin between the specified <paramref name="window"/> 
        ''' and the nearest border of the active screeen is lower than the value specified in <paramref name="threshold"/>,
        ''' then it docks the window to the border. 
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="window">
        ''' The magnetic window.
        ''' </param>
        ''' 
        ''' <param name="windowPosHandle">
        ''' A pointer to a <see cref="Interop.Win32.Types.WindowPos"/> structure that contains the 
        ''' new size and position of the <paramref name="window"/>.
        ''' </param>
        ''' 
        ''' <param name="threshold">
        ''' The minimum threshold that the window needs to dock it on the nearest desktop border.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        Protected Overridable Sub DockToNearestScreenBorder(ByVal window As IWin32Window,
                                                            ByVal windowPosHandle As IntPtr,
                                                            Optional ByVal threshold As Integer = 0I)
 
            Dim workingArea As Rectangle =
                Screen.FromControl(DirectCast(window, Control)).WorkingArea ' Active screen.
 
            workingArea.Width = 0
            workingArea.Height = 0
 
            Screen.AllScreens.ToList.ForEach(
                Sub(scr As Screen)
                    workingArea.Width += scr.WorkingArea.Width
                    workingArea.Height += scr.WorkingArea.Height
                End Sub)
 
            Dim windowPos As WindowPos =
                CType(Marshal.PtrToStructure(windowPosHandle, GetType(WindowPos)), WindowPos)
 
            If (windowPos.Y = 0) OrElse (windowPos.X = 0) Then
                ' Nothing to do.
                Exit Sub
            End If
 
            Dim win32Rect As Rect
            Dim rect As Rectangle
            NativeMethods.GetWindowRect(window.Handle, win32Rect)
            rect = win32Rect
 
            ' Top border
            If ((windowPos.Y >= -threshold) AndAlso
               ((workingArea.Y > 0) AndAlso (windowPos.Y <= (threshold + workingArea.Y)))) _
            OrElse ((workingArea.Y <= 0) AndAlso (windowPos.Y <= threshold)) Then
 
                windowPos.Y = workingArea.Y
 
            End If
 
            ' Left border
            If (windowPos.X >= (workingArea.X - threshold)) AndAlso
               (windowPos.X <= (workingArea.X + threshold)) Then
 
                windowPos.X = workingArea.X
 
            ElseIf (windowPos.X <= (workingArea.X - threshold)) AndAlso
                   Not (Me.allowOffscreenB) Then
 
                windowPos.X = workingArea.X
 
            End If
 
            ' Right border.
            If ((windowPos.X + rect.Width) <= (workingArea.Right + threshold)) AndAlso
               ((windowPos.X + rect.Width) >= (workingArea.Right - threshold)) Then
 
                windowPos.X = (workingArea.Right - rect.Width)
 
            ElseIf ((windowPos.X + rect.Width) >= (workingArea.Right + threshold)) AndAlso
                   Not (Me.allowOffscreenB) Then
 
                windowPos.X = (workingArea.Right - rect.Width)
 
            End If
 
            ' Bottom border.
            If ((windowPos.Y + rect.Height) <= (workingArea.Bottom + threshold)) AndAlso
               ((windowPos.Y + rect.Height) >= (workingArea.Bottom - threshold)) Then
 
                windowPos.Y = (workingArea.Bottom - rect.Height)
 
            ElseIf ((windowPos.Y + rect.Height) >= (workingArea.Bottom + threshold)) AndAlso
                   Not (Me.allowOffscreenB) Then
 
                windowPos.Y = (workingArea.Bottom - rect.Height)
 
            End If
 
            ' Marshal it back.
            Marshal.StructureToPtr(structure:=windowPos, ptr:=windowPosHandle, fDeleteOld:=True)
 
        End Sub
 
#End Region
 
#Region " Window Procedure (WndProc) "
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Invokes the default window procedure associated with this window to process windows messages.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="m">
        ''' A <see cref="T:Message"/> that is associated with the current Windows message.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        <DebuggerStepThrough>
        Protected Overrides Sub WndProc(ByRef m As Message)
 
            Select Case m.Msg
 
                Case WindowsMessages.WmSizing
                    Me.isResizing = True
 
                Case WindowsMessages.WmExitSizeMove
                    Me.isResizing = False
 
                Case WindowsMessages.WmWindowPosChanging
 
                    If Not (Me.isResizing) AndAlso (Me.enabledB) Then
                        Me.DockToNearestScreenBorder(window:=Me.ownerWindowB,
                                                     windowPosHandle:=m.LParam,
                                                     threshold:=Me.thresholdB)
                    End If
 
            End Select
 
            MyBase.WndProc(m)
 
        End Sub
 
#End Region
 
#Region " Hidden Base Members "
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Function ReferenceEquals(ByVal objA As Object, ByVal objB As Object) As Boolean
            Return Object.ReferenceEquals(objA, objB)
        End Function
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Function GetHashCode() As Integer
            Return MyBase.GetHashCode
        End Function
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Function [GetType]() As Type
            Return MyBase.GetType
        End Function
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Function Equals(ByVal obj As Object) As Boolean
            Return MyBase.Equals(obj)
        End Function
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Function ToString() As String
            Return MyBase.ToString
        End Function
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Sub AssignHandle(ByVal handle As IntPtr)
            MyBase.AssignHandle(handle)
        End Sub
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Sub CreateHandle(ByVal cp As CreateParams)
            MyBase.CreateHandle(cp)
        End Sub
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Sub DestroyHandle()
            MyBase.DestroyHandle()
        End Sub
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Sub ReleaseHandle()
            MyBase.ReleaseHandle()
        End Sub
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Function FromHandle(ByVal handle As IntPtr) As NativeWindow
            Return NativeWindow.FromHandle(handle)
        End Function
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Function GetLifeTimeService() As Object
            Return MyBase.GetLifetimeService
        End Function
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Function InitializeLifeTimeService() As Object
            Return MyBase.InitializeLifetimeService
        End Function
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Function CreateObjRef(ByVal requestedType As Type) As System.Runtime.Remoting.ObjRef
            Return MyBase.CreateObjRef(requestedType)
        End Function
 
        <EditorBrowsable(EditorBrowsableState.Never)>
        <DebuggerNonUserCode>
        Public Shadows Sub DefWndProc(ByRef m As Message)
            MyBase.DefWndProc(m)
        End Sub
 
#End Region
 
#Region " IDisposable Implementation "
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' To detect redundant calls when disposing.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        Protected isDisposed As Boolean
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Releases all the resources used by this instance.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        <DebuggerStepThrough>
        Public Sub Dispose() Implements IDisposable.Dispose
 
            Me.Dispose(isDisposing:=True)
            GC.SuppressFinalize(obj:=Me)
 
        End Sub
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
        ''' Releases unmanaged and - optionally - managed resources.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="isDisposing">
        ''' <see langword="True"/>  to release both managed and unmanaged resources; 
        ''' <see langword="False"/> to release only unmanaged resources.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        <DebuggerStepThrough>
        Protected Overridable Sub Dispose(ByVal isDisposing As Boolean)
 
            If (Not Me.isDisposed) AndAlso (isDisposing) Then
 
                With Me
                    .enabledB = False
                    .AllowOffscreen = True
                    .thresholdB = 0
                End With
 
                MyBase.ReleaseHandle()
                MyBase.DestroyHandle()
 
            End If
 
            Me.isDisposed = True
 
        End Sub
 
#End Region
 
    End Class
 
#End Region

P/Invokes:

Código

        <SuppressUnmanagedCodeSecurity>
        <DllImport("user32.dll", SetLastError:=True)>
        Public Shared Function GetWindowRect(ByVal hwnd As IntPtr,
                                             ByRef rect As Rect
        ) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

Código

Public Enum WindowsMessages As Integer
 
        WmSizing = &H214
        WmExitSizeMove = &H232
        WmWindowPosChanging = &H46
 
End Enum

Código

Imports System
Imports System.Diagnostics
Imports System.Linq
Imports System.Runtime.InteropServices
 
#Region " Window Pos "
 
    ''' ----------------------------------------------------------------------------------------------------
    ''' <summary>
    ''' Contains information about the size and position of a window.
    ''' </summary>
    ''' ----------------------------------------------------------------------------------------------------
    ''' <remarks>
    ''' <see href="http://msdn.microsoft.com/en-us/library/windows/desktop/ms632612%28v=vs.85%29.aspx"/>
    ''' </remarks>
    ''' ----------------------------------------------------------------------------------------------------
    <DebuggerStepThrough>
    <StructLayout(LayoutKind.Sequential)>
    Public Structure WindowPos
 
#Region " Fields "
 
        ''' <summary>
        ''' A handle to the window.
        ''' </summary>
        Public Hwnd As IntPtr
 
        ''' <summary>
        ''' The position of the window in Z order (front-to-back position). 
        ''' This member can be a handle to the window behind which this window is placed, 
        ''' or can be one of the special values listed with the 'SetWindowPos' function. 
        ''' </summary>
        Public HwndInsertAfter As IntPtr
 
        ''' <summary>
        ''' The position of the left edge of the window.
        ''' </summary>
        Public X As Integer
 
        ''' <summary>
        ''' The position of the top edge of the window.
        ''' </summary>
        Public Y As Integer
 
        ''' <summary>
        ''' The window width, in pixels.
        ''' </summary>
        Public Width As Integer
 
        ''' <summary>
        ''' The window height, in pixels.
        ''' </summary>
        Public Height As Integer
 
        ''' <summary>
        ''' Flag containing the window position.
        ''' </summary>
        Public Flags As Integer
 
#End Region
 
    End Structure
 
#End Region

Código

Imports System
Imports System.Diagnostics
Imports System.Drawing
Imports System.Linq
Imports System.Runtime.InteropServices
 
#Region " Rect "
 
    ''' ----------------------------------------------------------------------------------------------------
    ''' <summary>
    ''' Defines the coordinates of the upper-left and lower-right corners of a rectangle.
    ''' </summary>
    ''' ----------------------------------------------------------------------------------------------------
    ''' <remarks>
    ''' <see href="http://msdn.microsoft.com/en-us/library/windows/desktop/dd162897%28v=vs.85%29.aspx"/>
    ''' <para></para>
    ''' <see href="http://www.pinvoke.net/default.aspx/Structures/rect.html"/>
    ''' </remarks>
    ''' ----------------------------------------------------------------------------------------------------
    <DebuggerStepThrough>
    <StructLayout(LayoutKind.Sequential)>
    Public Structure Rect
 
#Region " Properties "
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets or sets the x-coordinate of the upper-left corner of the rectangle.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <value>
        ''' The x-coordinate of the upper-left corner of the rectangle.
        ''' </value>
        ''' ----------------------------------------------------------------------------------------------------
        Public Property Left As Integer
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets or sets the y-coordinate of the upper-left corner of the rectangle.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <value>
        ''' The y-coordinate of the upper-left corner of the rectangle.
        ''' </value>
        ''' ----------------------------------------------------------------------------------------------------
        Public Property Top As Integer
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets or sets the x-coordinate of the lower-right corner of the rectangle.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <value>
        ''' The x-coordinate of the lower-right corner of the rectangle.
        ''' </value>
        ''' ----------------------------------------------------------------------------------------------------
        Public Property Right As Integer
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets or sets the y-coordinate of the lower-right corner of the rectangle.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <value>
        ''' The y-coordinate of the lower-right corner of the rectangle.
        ''' </value>
        ''' ----------------------------------------------------------------------------------------------------
        Public Property Bottom As Integer
 
#End Region
 
#Region " Constructors "
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Initializes a new instance of the <see cref="Rect"/> struct.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="left">
        ''' The x-coordinate of the upper-left corner of the rectangle.
        ''' </param>
        ''' 
        ''' <param name="top">
        ''' The y-coordinate of the upper-left corner of the rectangle.
        ''' </param>
        ''' 
        ''' <param name="right">
        ''' The x-coordinate of the lower-right corner of the rectangle.
        ''' </param>
        ''' 
        ''' <param name="bottom">
        ''' The y-coordinate of the lower-right corner of the rectangle.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        Public Sub New(ByVal left As Integer,
                       ByVal top As Integer,
                       ByVal right As Integer,
                       ByVal bottom As Integer)
 
            Me.Left = left
            Me.Top = top
            Me.Right = right
            Me.Bottom = bottom
 
        End Sub
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Initializes a new instance of the <see cref="Rect"/> struct.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="rect">
        ''' The <see cref="Rectangle"/>.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        Public Sub New(ByVal rect As Rectangle)
 
            Me.New(rect.Left, rect.Top, rect.Right, rect.Bottom)
 
        End Sub
 
#End Region
 
#Region " Operator Conversions "
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Performs an implicit conversion from <see cref="Rect"/> to <see cref="Rectangle"/>.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="rect">The <see cref="Rect"/>.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' The resulting <see cref="Rectangle"/>.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        Public Shared Widening Operator CType(rect As Rect) As Rectangle
 
            Return New Rectangle(rect.Left, rect.Top, (rect.Right - rect.Left), (rect.Bottom - rect.Top))
 
        End Operator
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Performs an implicit conversion from <see cref="Rectangle"/> to <see cref="Rect"/>.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="rect">The <see cref="Rectangle"/>.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' The resulting <see cref="Rect"/>.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        Public Shared Widening Operator CType(rect As Rectangle) As Rect
 
            Return New Rect(rect)
 
        End Operator
 
#End Region
 
    End Structure
 
#End Region

Espero que esto les pueda servir de ayuda.

Saludos!