我的任务是将AutoCAD插件从VBA翻译成VB.NET，我现在有点卡住了。
我正在处理的命令创建一个新图层（或者如果它已经存在则选择它作为活动图层），然后执行2“-INSERT”命令，给出用户选择的点和dwg文件。然后，将前一个活动层重置为活动层。
insert-command看起来像这样：
-INSERT
C:\path\to\file.dwg
<point.x>,<point.y>,<point.z>
<documentScale>
注意：命令中的所有换行符都会添加为vbCR（不是vbCrLf）。
我的问题是，如何在.NET中针对ObjectARX实现相同的结果？我不能使用SendStringToExecute，因为它是异步的（没有回调），换句话说，一旦执行完毕，我就无法重置当前层。必须有一些方法可以在纯.NET代码中复制此功能，可能使用BlockTable，但我不知道如何。
我已尝试按照此处找到的文章：http://through-the-interface.typepad.com/through_the_interface/2006/08/import_blocks_f.html，但这根本没有对文档产生明显影响。我也尝试使用myDatabase.Insert(transform, otherDatabase, False)，并且命令提示符说已经存在的块已经存在并因此被跳过，但我仍然没有看到任何变化。我不知道“-INSERT”命令在幕后实际上有多么神奇，但在.NET中复制它是否可行？或者它是否可以被称为普通方法（而不是作为发送给AutoCAD处理的文本命令）？
答案 0 :(得分：5)
“通过界面”帖子中的代码示例导入块，但不将它们插入到图形中。您必须创建BlockReference并将其添加到模型空间。它还会插入文件中的所有块，而不是文件作为单个块。
以下是我用来将文件作为整个块导入的代码。此函数返回可以插入到图形中的块引用。
Private Shared Function InsertFile(ByVal FileName as String, ByVal dwgdb As Database, ByVal tr As Transaction) As BlockReference
Dim br As BlockReference
Dim id As ObjectId
'use a temporary database
Using TempDB As New Database(False, True)
'Get block table
Dim bt As BlockTable = tr.GetObject(dwgdb.BlockTableId, OpenMode.ForWrite, False)
'Create unique block name
Dim BlockName As String = FileName.Replace("\", "").Replace(":", "").Replace(".", "")
'check if block already exists
If Not bt.Has(BlockName) Then
'check if file exists
If IO.File.Exists(FileName) Then
'read in the file into the temp database
TempDB.ReadDwgFile(FileName, IO.FileShare.Read, True, Nothing)
'insert the tempdb into the current drawing db, id is the new block id
id = dwgdb.Insert(BlockName, TempDB, True)
Else
'Throw exception for missing file
Throw New System.Exception(String.Format("File {0} is not found for library item {1}", FileName, item.PartNo))
End If
Else
id = bt.Item(BlockName)
End If
'create a new block reference
br = New BlockReference(New Point3d(0, 0, 0), id)
End Using
Return br
End Function
这是使用该函数将块插入文件的示例。在这个例子中，我使用一个夹具，它允许用户将对象放到他们想要的位置，否则你可以设置位置。
' Get Editor
Dim ed As Editor = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument.Editor
' Get Database
Dim dwg As Database = ed.Document.Database
'Lock document
Using dl As DocumentLock = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument.LockDocument()
'### Changed Try Finally to using, try was hiding errors
'Begin Transaction
Using trans As Transaction = dwg.TransactionManager.StartTransaction()
Dim blockRef As BlockReference = InsertFile(FileName, dwg, trans)
'check if layer exists/create
AcadUtil.AcadFunctions.CheckLayer(LayerName, trans, dwg)
blockRef.Layer = LayerName
'set focus to the editor
Autodesk.AutoCAD.Internal.Utils.SetFocusToDwgView()
'have the user pick insert point
Dim BlockMove As New AcadJigs.JigBlockMove(blockRef, False, 0)
ed.Drag(BlockMove)
'optionally you could just set the .Position of the block reference
' add it to the current space, first open the current space for write
Dim btr As BlockTableRecord = trans.GetObject(dwg.CurrentSpaceId, OpenMode.ForWrite, True, True)
' Add block reference to current space
btr.AppendEntity(blockRef)
'Capture the handle
handle = blockRef.Handle.Value.ToString
' remember to tell the transaction about the new block reference so that the transaction can autoclose it
trans.AddNewlyCreatedDBObject(blockRef, True)
'commit the transaction
trans.Commit()
End Using
End Using
这里也是我调用的CheckLayer函数。
Public Shared Sub CheckLayer(ByVal Name As String, ByVal tr As Transaction, ByVal dwg As Database)
Dim lt As LayerTable = CType(tr.GetObject(dwg.LayerTableId, OpenMode.ForWrite), LayerTable)
If lt.Has(Name) Then
Return
Else
Dim ly As New LayerTableRecord
ly.Name = Name
lt.Add(ly)
tr.AddNewlyCreatedDBObject(ly, True)
End If
End Sub
正如笔记一样，Kean的博客是一个很好的资源，我几乎从那里学到了所有上述代码。
为了完整起见，这里是插入代码中的Jig类i引用，
Class JigBlockMove
Inherits EntityJig
Private _CenterPt As Point3d
Private _ActualPoint As Point3d
Private _LockZ As Boolean
Private _Z As Double
Public ReadOnly Property SelectedPoint() As Point3d
Get
Return _ActualPoint
End Get
End Property
Public Sub New(ByVal BlockRef As BlockReference, ByVal LockZ As Boolean, ByVal Z As Double)
MyBase.New(BlockRef)
_CenterPt = BlockRef.Position
_LockZ = LockZ
_Z = Z
End Sub
Protected Overloads Overrides Function Sampler(ByVal prompts As JigPrompts) As SamplerStatus
Dim jigOpts As New JigPromptPointOptions()
jigOpts.UserInputControls = (UserInputControls.Accept3dCoordinates Or UserInputControls.NoZeroResponseAccepted Or UserInputControls.NoNegativeResponseAccepted)
jigOpts.Message = vbLf & "Enter insert point: "
Dim dres As PromptPointResult = prompts.AcquirePoint(jigOpts)
If _ActualPoint = dres.Value Then
Return SamplerStatus.NoChange
Else
_ActualPoint = dres.Value
End If
Return SamplerStatus.OK
End Function
Protected Overloads Overrides Function Update() As Boolean
If _LockZ Then
_CenterPt = New Point3d(_ActualPoint.X, _ActualPoint.Y, _Z)
Else
_CenterPt = _ActualPoint
End If
Try
DirectCast(Entity, BlockReference).Position = _CenterPt
Catch generatedExceptionName As System.Exception
Return False
End Try
Return True
End Function
Public Function GetEntity() As Entity
Return Entity
End Function
End Class
关于在.NET ObjectARX中工作的一个注意事项，AutoCAD的单线程特性存在问题，并且.NET垃圾收集器在单独的线程上运行。如果创建任何未添加到数据库的临时AutoCAD对象，则必须明确调用.Dispose()，否则AutoCAD可能会崩溃！崩溃似乎也是随机的，因为它将由垃圾收集器线程触发。请参阅此帖子http://through-the-interface.typepad.com/through_the_interface/2008/06/cleaning-up-aft.html。