System.ArgumentException при попытке снять скриншот с игры и получить цвет пиксела

Public Function GetScreenshot() As Bitmap
        Dim controlSize As Size = GetControlSize()
        Dim bmp As New System.Drawing.Bitmap(controlSize.Width, controlSize.Height)
        Dim g As System.Drawing.Graphics = System.Drawing.Graphics.FromImage(bmp)      
        Dim dc As IntPtr = g.GetHdc()
 
        SendMessage(game, WM_PAINT, IntPtr.Zero, IntPtr.Zero)
        PrintWindow(game, dc, 0)
 
        g.ReleaseHdc()
        g.Dispose()
        Return bmp
    End Function

 GetScreenshot().GetPixel(x, y)

Imports System.Runtime.InteropServices
 
Public Class Form1
 
    Public game As Integer
    'hwnd
 
    Public gState As String
 
    Public combi As Integer = 1
    'combo index
 
    Public wins As Integer = 0
    Public loses As Integer = 0
    'statistic
 
 
    Public f_350_350 = 25525116954
 
    'coords
 
    <StructLayout(LayoutKind.Sequential)> _
    Public Structure RECT
        Public Left As Integer
        Public Top As Integer
        Public Right As Integer
        Public Bottom As Integer
    End Structure
 
    Const WM_KEYDOWN As UInteger = &H100
    Const WM_KEYUP As UInteger = &H101
    Const WM_PAINT As Int32 = &HF
    Const WM_LBUTTONDOWN As Int32 = &H201
    Const WM_LBUTTONUP As Int32 = &H202
 
    <DllImport("User32.dll", SetLastError:=True)> _
    Private Shared Function PrintWindow(ByVal hwnd As IntPtr, ByVal hDC As IntPtr, ByVal nFlags As UInteger) As Boolean
    End Function
 
    <DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=False)> _
    Private Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal Msg As Int32, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr
    End Function
 
    Public Sub ClickControl(ByVal x As Integer, ByVal y As Integer)
        Dim coords As Integer = (y << 16) + x
        Dim lParam As New IntPtr(coords)
        PostMessage(game, WM_LBUTTONDOWN, IntPtr.Zero, lParam)
        PostMessage(game, WM_LBUTTONUP, IntPtr.Zero, lParam)
    End Sub
 
    Public Function GetControlSize() As Size
        Dim rect As RECT
        GetWindowRect(game, rect)
        Return New Size(rect.Right - rect.Left, rect.Bottom - rect.Top)
    End Function
    Public Function GetPx(ByVal lx, ByVal ly)
        Dim controlSize As Size = GetControlSize()
        Dim bmp As New System.Drawing.Bitmap(controlSize.Width, controlSize.Height)
        Dim g As System.Drawing.Graphics = System.Drawing.Graphics.FromImage(bmp)
        Dim dc As IntPtr = g.GetHdc()
 
        SendMessage(game, WM_PAINT, IntPtr.Zero, IntPtr.Zero)
        PrintWindow(game, dc, 0)
 
        g.ReleaseHdc()
        g.Dispose()
        Dim z = bmp.GetPixel(lx, ly)
        Dim zz = z.A.ToString + z.R.ToString + z.G.ToString + z.B.ToString
        Return zz.ToString
 
    End Function
 
    Public Function GetPixelColor(ByVal x As Integer, ByVal y As Integer) As Color
        'Return GetScreenshot().GetPixel(x, y)
    End Function
    <DllImport("user32.dll", SetLastError:=True)> _
    Private Shared Function PostMessage(ByVal hWnd As IntPtr, ByVal Msg As UInteger, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
    End Function
 
    <DllImport("user32.dll")> _
    Private Shared Function GetWindowRect(ByVal hWnd As IntPtr, ByRef lpRect As RECT) As <MarshalAs(UnmanagedType.Bool)> Boolean
    End Function
 
    <DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
    Private Shared Function FindWindow( _
     ByVal lpClassName As String, _
     ByVal lpWindowName As String) As IntPtr
    End Function
 
    Public Delegate Function CallBack(ByVal hWnd As Integer, ByVal lParam As Integer) As Boolean
    Public Declare Function EnumWindows Lib "user32" (ByVal x As CallBack, ByVal lParam As Integer) As Integer
    Public Declare Function EnumChildWindows Lib "user32" (ByVal hWndParent As System.IntPtr, ByVal x As CallBack, ByVal lParam As Integer) As Integer
    Dim list As New ArrayList()
 
    Public Function ReportMain(ByVal hwnd As Integer, ByVal lParam As Integer) As Boolean
        EnumChildWindows(hwnd, AddressOf ReportChild, 0)
        Return True
    End Function
 
    Public Function ReportChild(ByVal hWnd As Integer, ByVal lParam As Integer) As Boolean
        list.Add(hWnd)
        Return True
    End Function
 
    Public Function get_gstate()
        Dim a = GetPx(100, 105)
        Return a
    End Function
 
    Public Function get_fstate()
        Dim b = GetPx(350, 350)
 
        If b = f_350_350 Then
            Return "ok"
        End If
    End Function
 
 
    Public Function start_battle()
        ClickControl(50, 300)
        Me.combi = 1
    End Function
 
    Public Function addlog(ByVal txt)
        Log.Text = txt + vbNewLine + Log.Text
    End Function
 
    Public Function work()
 
        Dim a = get_gstate()
        Select Case a
            Case 255173148112
                '255917452
                ' loka
                'addlog(TimeString + ": Начинаю бой")
                start_battle()
            Case 255151617
                ' fight
                If get_fstate() = "ok" Then
                    ffight(combi)
                End If
            Case 255117118118
                ' ozhidanie konca boya
                combi = 1
            Case 255168151137
                ' mob not respawn
                ClickControl(370, 415) 'ok
            Case 255197184166
                addlog(TimeString + ": Победа")
                Me.wins += 1
                Label2.Text = "Победы: " + Me.wins.ToString
                ClickControl(350, 565) 'ok
            Case 255216188141
                addlog(TimeString + ": Победа +")
 
                Me.wins += 1
                Label2.Text = "Победы: " + Me.wins.ToString
                ClickControl(365, 635) 'ok
            Case Else
                ' takogo ne mozhet bit
 
                'addlog("Херня каято a = " + a)
        End Select
 
    End Function
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Dim gp = GetPixelColor(TextBox1.Text, TextBox2.Text)
        'Dim pixel = gp.A.ToString + gp.R.ToString + gp.G.ToString + gp.B.ToString
        'Dim val = TextBox1.Text + ", " + TextBox2.Text + " : " + pixel.ToString
        'TextBox3.Text += val + vbNewLine
        'start_battle()
        'ClickControl(TextBox1.Text, TextBox2.Text)
    End Sub
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim Handle As IntPtr = FindWindow(vbNullString, "eXtreme")
        ReportMain(Handle, 0)
        ReportChild(Handle, 0)
 
        For i = 0 To list.Count - 1
            Dim размер As RECT
 
            GetWindowRect(list.Item(i).ToString, размер)
            Dim ширина As Integer = размер.Right - размер.Left
            Dim высота As Integer = размер.Bottom - размер.Top
            If ширина = 730 And высота = 730 Then
                Me.Text = 1
                stext1.Text = "Окно найдено, можно начинать"
                stext1.ForeColor = Color.Green
                Label1.Text = list.Item(i)
                game = list.Item(i)
 
            End If
            'If (ширина <> 0 Or высота <> 0) Then
            'ListBox1.Items.Add(list.Item(i) & ", " & ширина & ", " & высота)
            'End If
 
 
        Next
    End Sub
    Public Function ffight(ByVal combi As Integer)
        Dim i = combi
        'addlog(TimeString + ": делаю удар " + i.ToString)
 
 
        'ClickControl(385, 290) 'top
        'ClickControl(410, 345) 'mid
        'ClickControl(390, 400) 'bot
        Select Case i
            Case 1
                ClickControl(390, 400)
                'ClickControl(385, 290)
                Me.combi = 2
            Case 2
                ClickControl(385, 290) 'top
                Me.combi = 3
            Case 3
                ClickControl(385, 290) 'top
                Me.combi = 4
            Case 4
                ClickControl(410, 345) 'mid
                Me.combi = 1
        End Select
 
 
    End Function
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        If Button2.Text = "Включить" Then
            Button2.Text = "Выключить"
            Button2.BackColor = Color.LimeGreen
            GameTimer.Enabled = True
        Else
            Button2.Text = "Включить"
            Button2.BackColor = Color.Pink
            GameTimer.Enabled = False
        End If
 
    End Sub
 
    Private Sub GameTimer_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles GameTimer.Tick
        work()
    End Sub
End Class