VB.NET ConsoleReader

Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Runtime.InteropServices
Imports System.Text

Namespace ConsoleReaderTest
    Public Class ConsoleReader
        Public Shared Function ReadFromBuffer(ByVal x As Short, ByVal y As Short, ByVal width As Short, ByVal height As Short) As IList(Of String)
            Dim lpBuffer As IntPtr = Marshal.AllocHGlobal(CInt(((width * height) * Marshal.SizeOf(GetType(CHAR_INFO)))))
            Dim list As New List(Of String)
            Try
                Dim dwBufferCoord As New COORD
                Dim lpReadRegion As New SMALL_RECT With { _
                    .Left = x, _
                    .Top = y, _
                    .Right = CShort(((x + width) - 1)), _
                    .Bottom = CShort(((y + height) - 1)) _
                }
                Dim dwBufferSize As New COORD With { _
                    .X = width, _
                    .Y = height _
                }

                If Not ConsoleReader.ReadConsoleOutput(ConsoleReader.GetStdHandle(-11), lpBuffer, dwBufferSize, dwBufferCoord, lpReadRegion) Then
                    Throw New Win32Exception(Marshal.GetLastWin32Error)
                End If

                Dim ptr As IntPtr = lpBuffer
                Dim i As Integer
                For i = 0 To height - 1
                    Dim builder As New StringBuilder
                    Dim j As Integer
                    For j = 0 To width - 1
                        Dim char_info As CHAR_INFO = DirectCast(Marshal.PtrToStructure(ptr, GetType(CHAR_INFO)), CHAR_INFO)
                        Dim chars As Char() = Console.OutputEncoding.GetChars(char_info.charData)
                        builder.Append(chars(0))
                        ptr = (ptr + Marshal.SizeOf(GetType(CHAR_INFO)))
                    Next j
                    list.Add(builder.ToString)
                Next i

            Finally
                Marshal.FreeHGlobal(lpBuffer)
            End Try
            Return list
        End Function

        <DllImport("kernel32.dll", SetLastError:=True)> _
        Private Shared Function GetStdHandle(ByVal nStdHandle As Integer) As IntPtr
        End Function

        <DllImport("kernel32.dll", SetLastError:=True)> _
        Private Shared Function ReadConsoleOutput(ByVal hConsoleOutput As IntPtr, ByVal lpBuffer As IntPtr, ByVal dwBufferSize As COORD, ByVal dwBufferCoord As COORD, ByRef lpReadRegion As SMALL_RECT) As Boolean
        End Function

        <StructLayout(LayoutKind.Sequential)> _
        Private Structure CHAR_INFO
            <MarshalAs(UnmanagedType.ByValArray, SizeConst:=2)> _
            Public charData As Byte()
            Public attributes As Short
        End Structure

        <StructLayout(LayoutKind.Sequential)> _
        Private Structure CONSOLE_SCREEN_BUFFER_INFO
            Public dwSize As COORD
            Public dwCursorPosition As COORD
            Public wAttributes As Short
            Public srWindow As SMALL_RECT
            Public dwMaximumWindowSize As COORD
        End Structure

        <StructLayout(LayoutKind.Sequential)> _
        Private Structure COORD
            Public X As Short
            Public Y As Short
        End Structure

        <StructLayout(LayoutKind.Sequential)> _
        Private Structure SMALL_RECT
            Public Left As Short
            Public Top As Short
            Public Right As Short
            Public Bottom As Short
        End Structure
    End Class
End Namespace