Read and display body from the file using SOLIDWORKS API

This VBA example demonstrates how to read the body geometry data from the external binary file. Load this data into the COM Stream and restore into the temp solid body using SOLIDWORKS API.
Body is displayed to the user and macro execution stops. Body is not present in the Feature Manager Tree and only visible in the graphics area.
Continue the macro execution to destroy the body.
Imports SolidWorks.Interop.sldworks
Imports SolidWorks.Interop.swconst
Imports System.IO
Imports System.Runtime.InteropServices
Imports System.Runtime.InteropServices.ComTypes

Module Module1

    Declare Function CreateStreamOnHGlobal Lib "ole32" (ByVal hGlobal As IntPtr, ByVal fDeleteOnRelease As Boolean, ByRef ppstm As IStream) As Long

    Const FILE_PATH As String = "D:\body.dat"

    Sub Main()

        Dim app As ISldWorks = CreateObject("SldWorks.Application")
        app.Visible = True

        Dim model As IModelDoc2
        model = app.ActiveDoc

        If Not model Is Nothing Then

            Dim body As IBody2 = LoadBodyFromFile(app, FILE_PATH)

            If Not body Is Nothing Then
                body.Display3(model, RGB(255, 255, 0), swTempBodySelectOptions_e.swTempBodySelectOptionNone)
                Console.ReadLine()
            Else
                Throw New Exception("Failed to restore the body")
            End If

        Else
            Throw New Exception("Please open the model")
        End If

    End Sub

    Function LoadBodyFromFile(app As ISldWorks, filePath As String) As IBody2

        Dim stream As IStream = Nothing

        CreateStreamOnHGlobal(IntPtr.Zero, True, stream)

        Dim comStream = New ComStream(stream, True, True)

        Using fileStream = File.OpenRead(filePath)
            fileStream.CopyTo(comStream)
            comStream.Seek(0, SeekOrigin.Begin)
        End Using

        Dim modeler As IModeler = app.IGetModeler()

        Return modeler.Restore(stream)

    End Function

End Module

Public Class ComStream
    Inherits Stream

    Private ReadOnly m_ComStream As IStream
    Private ReadOnly m_Commit As Boolean
    Private m_IsWritable As Boolean

    Public Sub New(ByRef comStream As IStream, writable As Boolean, Optional commit As Boolean = True)

        If comStream Is Nothing Then
            Throw New ArgumentNullException(NameOf(comStream))
        End If

        m_ComStream = comStream
        m_IsWritable = writable
        m_Commit = commit

    End Sub

    Public Overrides ReadOnly Property CanRead() As Boolean
        Get
            Return True
        End Get
    End Property

    Public Overrides ReadOnly Property CanSeek() As Boolean
        Get
            Return True
        End Get
    End Property

    Public Overrides ReadOnly Property CanWrite() As Boolean
        Get
            Return m_IsWritable
        End Get
    End Property

    Public Overrides ReadOnly Property Length As Long
        Get
            Const STATSFLAG_NONAME As Integer = 1

            Dim stats As ComTypes.STATSTG = Nothing
            m_ComStream.Stat(stats, STATSFLAG_NONAME)

            Return stats.cbSize
        End Get
    End Property

    Public Overrides Property Position() As Long
        Get
            Return Seek(0, SeekOrigin.Current)
        End Get
        Set(ByVal Value As Long)
            Seek(Value, SeekOrigin.Begin)
        End Set
    End Property

    Public Overrides Sub Flush()
        If m_Commit Then
            Const STGC_DEFAULT As Integer = 0
            m_ComStream.Commit(STGC_DEFAULT)
        End If
    End Sub

    Public Overrides Sub SetLength(ByVal Value As Long)
        m_ComStream.SetSize(Value)
    End Sub

    Public Overrides Sub Write(buffer() As Byte, offset As Integer, count As Integer)
        If offset <> 0 Then
            Dim bufferSize As Integer
            bufferSize = buffer.Length - offset
            Dim tmpBuffer(bufferSize) As Byte
            Array.Copy(buffer, offset, tmpBuffer, 0, bufferSize)
            m_ComStream.Write(tmpBuffer, bufferSize, Nothing)
        Else
            m_ComStream.Write(buffer, count, Nothing)
        End If
    End Sub

    Public Overrides Function Read(buffer() As Byte, offset As Integer, count As Integer) As Integer

        Dim bytesRead As Integer = 0
        Dim boxBytesRead As Object = bytesRead
        Dim hObject As GCHandle

        Try
            hObject = GCHandle.Alloc(boxBytesRead, GCHandleType.Pinned)
            Dim pBytesRead As IntPtr = hObject.AddrOfPinnedObject()

            If offset <> 0 Then
                Dim tmpBuffer(count - 1) As Byte
                m_ComStream.Read(tmpBuffer, count, pBytesRead)
                bytesRead = CInt(boxBytesRead)
                Array.Copy(tmpBuffer, 0, buffer, offset, bytesRead)
            Else
                m_ComStream.Read(buffer, count, pBytesRead)
                bytesRead = CInt(boxBytesRead)
            End If

        Finally
            If hObject.IsAllocated Then
                hObject.Free()
            End If
        End Try

        Return bytesRead

    End Function

    Public Overrides Function Seek(offset As Long, origin As SeekOrigin) As Long

        Dim curPosition As Long = 0
        Dim boxCurPosition As Object = curPosition
        Dim hObject As GCHandle

        Try
            hObject = GCHandle.Alloc(boxCurPosition, GCHandleType.Pinned)
            Dim pCurPosition As IntPtr = hObject.AddrOfPinnedObject()

            m_ComStream.Seek(offset, origin, pCurPosition)
            curPosition = CLng(boxCurPosition)
        Finally
            If hObject.IsAllocated Then
                hObject.Free()
            End If
        End Try

        Return curPosition
    End Function

    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
        Try
            If disposing Then
                m_IsWritable = False
            End If
        Finally
            MyBase.Dispose(disposing)
        End Try
    End Sub

    Protected Overrides Sub Finalize()
        Dispose(False)
    End Sub

End Class