# Insert External Reference Example (VB.NET)

This example shows how to insert an external reference to a drawing document.

    '--------------------------------------------------------------
    'Preconditions:
    ' 1. Create a VB.NET Windows console project.
    ' 2. Copy and paste this example into the VB.NET IDE.
    ' 3. Add a reference to:
    '    install_dir\APISDK\tlb\DraftSight.Interop.dsAutomation.dll.
    ' 4. Start DraftSight and open a new document.
    ' 5. If C:\Block.dwg exists, then skip this step.
    '    - or -
    '    If C:\Block.dwg does not exist, then construct
    '    some geometry in the drawing, save the drawing
    '    as C:\Block.dwg, and open a new drawing document.
    ' 6. Start debugging the project.
    '
    ' Postconditions: A message box pops up when an external reference
    ' is inserted in the drawing document.
    '----------------------------------------------------------------
    Imports DraftSight.Interop.dsAutomation

    Module Module1

        Sub Main()

            Dim dsApp As Application
            Dim dsDoc As Document
            Dim dsModel As Model
            Dim dsSketchManager As SketchManager
            Dim dsExtReference As BlockInstance
    	Dim dsReference as ExternalReference
            Dim pathName As String
            Dim insertX, insertY, insertZ, scaleValue, rotation As Double

            'Connect to DraftSight
            dsApp = GetObject(, "DraftSight.Application")
    	dsApp.AbortRunningCommand() ' abort any command currently running in DraftSight to avoid nested commands

            'Get active document
            dsDoc = dsApp.GetActiveDocument()

            If Not dsDoc Is Nothing Then
                'Get model space
                dsModel = dsDoc.GetModel()
                'Get Sketch Manager
                dsSketchManager = dsModel.GetSketchManager()

                'External reference parameters (rotation value should be in radians)
                pathName = "C:\Block.dwg"
                insertX = 0.0#
                insertY = 0.0#
                insertZ = 0.0#
                scaleValue = 1.0#
                rotation = 0.0#
                'Add a Block instance
                dsExtReference = dsSketchManager.InsertExternalReference(pathName, insertX, insertY, insertZ, scaleValue, rotation)

                If dsExtReference Is Nothing Then
                    MsgBox(pathName & " file was not found.")
                Else
                    MsgBox("An external reference was added to the drawing.")
                    Dim references As Object
                    Dim reference As Object
                    references = dsDoc.GetExternalReferences
                    reference = references(0)
                    dsReference = reference
                    If Not dsReference Is Nothing Then
                        MsgBox("Name of external reference " & dsReference.Name & ".")
                    End If

                End If
            Else
                MsgBox("There are no open documents in DraftSight.")
            End If
        End Sub
    End Module