Как изменить разрешение макроса

Imports System.Runtime.InteropServices

Public Class Form1

    <StructLayout(LayoutKind.Sequential)> _

  Public Structure DEVMODE1

        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=32)> _

        Public dmDeviceName As String

        Public dmSpecVersion As Short

        Public dmDriverVersion As Short

        Public dmSize As Short

        Public dmDriverExtra As Short

        Public dmFields As Integer

        Public dmOrientation As Short

        Public dmPaperSize As Short

        Public dmPaperLength As Short

        Public dmPaperWidth As Short

        Public dmScale As Short

        Public dmCopies As Short

        Public dmDefaultSource As Short

        Public dmPrintQuality As Short

        Public dmColor As Short

        Public dmDuplex As Short

        Public dmYResolution As Short

        Public dmTTOption As Short

        Public dmCollate As Short

        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=32)> _

        Public dmFormName As String

        Public dmLogPixels As Short

        Public dmBitsPerPel As Short

        Public dmPelsWidth As Integer

        Public dmPelsHeight As Integer

        Public dmDisplayFlags As Integer

        Public dmDisplayFrequency As Integer

        Public dmICMMethod As Integer

        Public dmICMIntent As Integer

        Public dmMediaType As Integer

        Public dmDitherType As Integer

        Public dmReserved1 As Integer

        Public dmReserved2 As Integer

        Public dmPanningWidth As Integer

        Public dmPanningHeight As Integer

    End Structure

    Private Class User_32

        <DllImport(«user32.dll»)> _

        Public Shared Function EnumDisplaySettings(ByVal deviceName As String, ByVal modeNum As Integer, ByRef devMode As DEVMODE1) As Integer

        End Function

        <DllImport(«user32.dll»)> _

        Public Shared Function ChangeDisplaySettings(ByRef devMode As DEVMODE1, ByVal flags As Integer) As Integer

        End Function

        Public Const ENUM_CURRENT_SETTINGS As Integer = -1

        Public Const CDS_UPDATEREGISTRY As Integer = &H1

        Public Const CDS_TEST As Integer = &H2

        Public Const DISP_CHANGE_SUCCESSFUL As Integer = 0

        Public Const DISP_CHANGE_RESTART As Integer = 1

        Public Const DISP_CHANGE_FAILED As Integer = -1

    End Class

    Private Class CResolution

        Public Sub New(ByVal a As Integer, ByVal b As Integer)

            Dim screen__1 As Screen = Screen.PrimaryScreen

            Dim iWidth As Integer = a

            Dim iHeight As Integer = b

            Dim dm As New DEVMODE1()

            dm.dmDeviceName = New [String](New Char(31) {})

            dm.dmFormName = New [String](New Char(31) {})

            dm.dmSize = CShort(Marshal.SizeOf(dm))

            If 0 <> User_32.EnumDisplaySettings(Nothing, User_32.ENUM_CURRENT_SETTINGS, dm) Then

                dm.dmPelsWidth = iWidth

                dm.dmPelsHeight = iHeight

                Dim iRet As Integer = User_32.ChangeDisplaySettings(dm, User_32.CDS_TEST)

                If iRet = User_32.DISP_CHANGE_FAILED Then

                    MessageBox.Show(«Unable to process your request»)

                    MessageBox.Show(«Description: Unable To Process Your Request. Sorry For This Inconvenience.», «Information», MessageBoxButtons.OK, MessageBoxIcon.Information)

                Else

                    iRet = User_32.ChangeDisplaySettings(dm, User_32.CDS_UPDATEREGISTRY)

                    Select Case iRet

                        Case User_32.DISP_CHANGE_SUCCESSFUL

                            If True Then

                                Exit Select

                                ‘successfull change

                            End If

                        Case User_32.DISP_CHANGE_RESTART

                            If True Then

                                MessageBox.Show(«Description: You Need To Reboot For The Change To Happen.» & vbLf & » If You Feel Any Problem After Rebooting Your Machine» & vbLf & «Then Try To Change Resolution In Safe Mode.», «Information», MessageBoxButtons.OK, MessageBoxIcon.Information)

                                Exit Select

                                ‘windows 9x series you have to restart

                            End If

                        Case Else

                            If True Then

                                MessageBox.Show(«Description: Failed To Change The Resolution.», «Information», MessageBoxButtons.OK, MessageBoxIcon.Information)

                                Exit Select

                                ‘failed to change

                            End If

                    End Select

                End If

            End If

        End Sub

    End Class

    Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim ChangeRes As New CResolution(800, 600)

    End Sub

End Class