AutoCAD DevBlog

Reach functions of a .NET plug-in from another application (out-of-process)

By Balaji Ramamoorthy

Issue

I wrote a .NET plugin and created a COM interface for it to enable driving AutoCAD from my application. Some things seem to work, but e.g. MdiActiveDocument is null and Editor.WriteMessage returns eNotApplicable inside my .NET functions when called from another application through its COM interface. However, when these functions are called from VBA (in-process), then everything is fine. What is the problem?

Solution

The problem is that your COM object is not in the STA. So you are trying to access AutoCAD from a thread other than its main thread. This won't work.

You have 2 ways to solve this problem:

1. Derive your COM object from System.EnterpriseServices.ServicedComponent
2. Or transition into the main thread "manually" in each method. Something like this:
control.Invoke(realMethod); Where control is any arbitrary window that was created on the main thread.

Here is the implementation of the 1st solution:

This is the plugin's code:

using Autodesk.AutoCAD.ApplicationServices;

 

namespace AcadCOM

{

    [Guid("16FF7627-8439-4ea5-A533-04FEDBD27B95")]

    public interface iAcadInProc

    {

        [DispId(1)]

        string Test();

    }

 

    [Guid("ACC23279-97EE-4ea3-AB08-0491889DEF34"),

    ClassInterface(ClassInterfaceType.None)]

    public class AcadInProc : System.EnterpriseServices.ServicedComponent, iAcadInProc

    {

        public AcadInProc()

        {

            Document doc = Application.DocumentManager.MdiActiveDocument;

            doc.Editor.WriteMessage("\nHello world from out of process.");

        }

 

        public string Test()

        {

            DocumentCollection docs = Application.DocumentManager;

 

            Document doc = docs.MdiActiveDocument;

 

            Autodesk.AutoCAD.EditorInput.Editor ed = doc.Editor;

 

            ed.WriteMessage("Test1 in " + doc.Name);

 

            return doc.Name;

        }

    }

}

This is the testing application's code:

using Autodesk.AutoCAD.Interop;

using System.Runtime.InteropServices;

 

private void button1_Click(object sender, EventArgs e)

{

    AcadApplication AcApp

        = (AcadApplication)Marshal.GetActiveObject("Autocad.Application");

    AcadCOM.iAcadInProc inProc

        = (AcadCOM.iAcadInProc)AcApp.GetInterfaceObject("AcadCOM.AcadInProc");

    string test = inProc.Test();

    MessageBox.Show(test);

}

The sample project is attached.

1. NetLoad CsMgdAcad1.dll into AutoCAD
2. Start MyExternalApp.exe
3. Click on the "Call Test" button

Download Sample

On a 64 bit system, registration of the COM wrapper needs an extra step. Please refer to this post for the details.

AutoCAD command in Managed C++/CLI

By Balaji Ramamoorthy

Here is a very simple example of an AutoCAD command using Managed C++. The buildable project is attached.

#pragma once

 

using namespace System;

using namespace Autodesk::AutoCAD::Runtime;

using namespace Autodesk::AutoCAD::ApplicationServices;

using namespace Autodesk::AutoCAD::EditorInput;

using namespace Autodesk::AutoCAD::DatabaseServices;

 

namespace MgdCpp

{

    public ref class MyClass

    {

        public:

 

        MyClass()

        {

        }

 

        [CommandMethod("MyCommand")]

        static void MyCommand()

        {

            DocumentCollection ^ docMgr

                    = Application::DocumentManager;

            Document ^ doc

                    = docMgr->MdiActiveDocument;

            Database ^ db

                    = doc->Database;

            Editor ^ ed = doc->Editor;

 

            PromptEntityResult ^per

                    = ed->GetEntity("Select an entity : ");

            if (per->Status != PromptStatus::OK)

                return;

 

            ObjectId oid = per->ObjectId;

 

            Transaction ^tr

                = db->TransactionManager->StartTransaction();

 

            Entity ^ent

                = (Entity ^)tr->GetObject(oid, OpenMode::ForRead);

 

            ed->WriteMessage(ent->GetRXClass()->Name);

 

            tr->Commit();

            tr->~Transaction();

        }

    };

}

 

[assembly: CommandClass(MgdCpp::MyClass::typeid)];

Download MgdCpp

Enumerate plotters in ActiveX

By Xiaodong Liang

The following VBA function enumerates all plotters that have corresponding .pc3 files, you can use this in your VBA applications:

Public Function GetPlotters() As Collection
Set GetPlotters = New Collection
Dim strPlotter As String
strPlotter = Dir(Application.Preferences.Files.PrinterConfigPath + "\*.pc3")
While Not strPlotter = ""
   GetPlotters.Add strPlotter
   strPlotter = Dir
   MsgBox strPlotter
Wend
End Function

A method to enumerate system printers (these are also available in the plot dialog of AutoCAD) is available on the following Microsoft knowledge base article:

http://support.microsoft.com/kb/166008

Remove anonymous groups with ARX

By Xiaodong Liang 

When an end user creates a 'group' in AutoCAD, it may be an anonymous group. However, all group (anonymous or otherwise) are stored in the Named Objects Dictionary under the key 'ACAD_GROUP'. If the group is anonymous, AutoCAD assigns it a value such as '*A1', '*A2' and so on. Although to the end user it's anonymous, the group has a unique key name in the AutoCAD database.

Users may add or remove entities from groups so it is possible to have empty groups. The code below is a small demo to remove an anonymous group.

 

static void removeGroup()

{

 

Acad::ErrorStatus es;

AcDbDictionary *pGroupDict;

AcDbGroup *pGroup;

AcDbDictionaryIterator *pDictIter;

AcDbObjectId groupId;

long numItems;

AcDbObjectIdArray groupMembers;

 

es =

acdbHostApplicationServices()->workingDatabase()->

   getGroupDictionary(pGroupDict,AcDb::kForWrite);

pDictIter = pGroupDict->newIterator();

 

for(; !pDictIter->done(); pDictIter->next())

{

    pDictIter->getObject(

        (AcDbObject*&)pGroup, AcDb::kForRead);

    // Is the group anonymous?

    if(pGroup->isAnonymous())

    {

        // Does the anonymous group have

        // any members associated with it?

        numItems = pGroup->numEntities();

        if(numItems > 0)

        {

            // Empty the group

            // Upgrade it first

            es = pGroup->upgradeOpen();

            es = pGroup->clear();

            es = pGroup->downgradeOpen();

 

            pGroup->close();

        }

 

        // Get the group ID and remove the

        // group from the dictionary

        groupId = pDictIter->objectId();

        es = pGroupDict->remove(groupId);

 

    } // if

 

    pGroup->close();

 

} // for

 

pGroupDict->close();

 

}

Finding the centroid of a region using LISP

By Xiaodong Liang

Issue
When a polyline is changed to a REGION you can get the center of gravity using MASSPROP. Variables exist for PERIMETER and AREA but not for the Center of Gravity. How can an Auto LISP routine extract the Center of Gravity from a region ?

Solution
Use the ActiveX interface to return the Cenroid property for a region. The following AutoLISP code does this:

(defun GetCentroid ()
 (vl-load-com)
 (setq anEnt (entsel "\nSelect A Region: "))
 (if anEnt
    (progn
      (setq anObj (vlax-ename->vla-object (car anEnt)))
      (princ (strcat "\nObject Name: " (setq objName (vla-Get-ObjectName
anObj))))
      (if (equal objName "AcDbRegion")
        (progn
          (setq vCentroid (vla-Get-Centroid anObj))
          (setq strCentroidProp (vl-princ-to-string (setq CentroidLst
(vlax-safearray->list (vlax-variant-value vCentroid)))))
          (if (< (length CentroidLst) 3)
           (setq CentroidLst (append CentroidLst (list 0.0)))
          )
          (princ (strcat "\nRegion Centroid: " strCentroidProp))
          (setvar "PDMODE" 3)
          (setq *MS* (vla-Get-ModelSpace (setq acadDoc
(vla-Get-ActiveDocument (setq acadApp (vlax-get-acad-object))))))
          (setq ptObj (vla-AddPoint *MS* (vlax-3d-Point CentroidLst)))
          (vla-Put-Color ptObj acYellow)
        )
        (princ "\nRegion was not selected !")
      )
    )
 )
 (princ)
)

(princ "\nGetCentroid loaded, type (GetCentroid) to run.")
(princ)

Change an Autodesk Exchange App installer from Single User to an All Users install

By default all Autodesk Exchange App installers are built to deploy the App bundles to the %APPDATA%\Autodesk\ApplicationPlugin folder. This folder is specifically a Single User install location, which means that if any other user logs onto the machine the App will need to be reinstalled for that user to be available, to that user.

The static install folder design (folders that cannot be changed) was specifically designed to help developers bypass the 2nd stage installer issues that comes with installing plugins, particularly difficult in AutoCAD, for the All User installation scenario. The way this was handled was to include a different static folder designed to support loading apps for the All User installation model, this folder can be found in the %PROGRAMDATA%\Autodesk\ApplicationPlugins folder.

The question is, how do I change an Exchange App Installer from being a Single User to an All User installer…

The answer - It’s all about changing the static folder installation path from the %APPDATA%\Autodesk\ApplicationPlugin (Single User) to %PROGRAMDATA%\Autodesk\ApplicationPlugins (All User). There are two ways that this can be achieved:

1) From a DOS command window:

c:\>msiexec /i MyExhangeApp.msi INSTALLDIR=C:\ProgramData\Autodesk\ApplicationPlugins AUTODESK=C:\ProgramData\Autodesk

2) You can edit the MSI directly using ORCA.exe and change the Directory Table->AUTODESK from AppDataFolder to CommonAppDataFolder

Setting the bulge of a polyline using ActiveX in LISP

By Xiaodong Liang

Issue
This is the Visual LISP code I have used to set a bulge for a polyline:

Command: !pline
#
Command: !mspace
#
Command: (vla-SetBulge mSpace pline 0 0.5)
; error: ActiveX Server returned the error: unknown name: SetBulge
Command: (vla-put-SetBulge pline 0 0.5)
; error: no function definition: VLA-PUT-SETBULGE
Command: (vlax-invoke-method mspace 'setbulge pline 0 0.5)
; error: ActiveX Server returned the error: unknown name: SETBULGE
Command: (vlax-put-property pline 'setbulge 0 0.5)
; error: ActiveX Server returned an error: Type mismatch

 

 

What is the correct syntax to use?

Solution
The documentation contains the information to answer this question. In the AutoCAD ActiveX and VBA Reference, go to Object Model -> Polyline Object -> SetBulge Method.

Then refer to the Visual LISP Developer's Guide: Using Visual LISP Functions with ActiveX Methods -> Determining How to Call a Function.

After reading these two references, you should notice that SetBulge is a method of the polyline object, not a Property nor a Method of the Model Space Collection (which is what the preceding code shows).

You'll find that the following code will set the bulge of a Polyline Object:

(vla-SetBulge myPolyObj 1 -0.42080)

Because it is easier to see this in context, code was copied from , and modified it to use the SetBulge method for a polyline:

(vl-load-com)
(defun a_Polyline_wArc()

  (setq acadapp (vlax-get-Acad-Object)
     acaddoc (vla-get-ActiveDocument acadapp)
     *ModelSpace*  (vla-get-ModelSpace acaddoc)
  )


  (setq pt1 (list 2.93905 1.87048 0.0))
  (setq pt2 (list 5.54349 4.81627 0.0))
  (setq pt3 (list 8.78096 4.97892 0.0))
  (setq pt4 (list 12.6153 1.20181 0.0))

  (setq Points (apply 'append (list pt1 pt2 pt3 pt4)))
  (setq ptlstlen (length Points))

  (setq PointDataA (vlax-make-safearray vlax-vbDouble (cons 0 (1- ptlstlen))))
  (vlax-safearray-fill PointDataA Points)
  (setq PointData (vlax-make-variant PointDataA (logior vlax-vbarray
vlax-vbDouble)))

  (setq myPolyObj (vla-addPolyline *ModelSpace* PointData))

  (vla-Put-Color myPolyObj acBlue)

  (setq strtWidth 1.0 endWidth 1.0 verticies (1- (/ ptlstlen 3)) indx 0)
  (while (< indx verticies)
       (vla-SetWidth myPolyObj indx strtWidth endWidth)
       (setq indx (1+ indx))
  )
  (vla-SetBulge myPolyObj 1 -0.42080)
  (vla-Update myPolyObj)
  
  (princ)
)
; (a_Polyline_wArc)

Entmake an mtext entity

By Xiaodong Liang

Issue
How can I use entmake in the following AutoLISP code to create an MTEXT entity? I can create a TEXT entity using similar code as below, but it does not work.

(defun CreateMText ()

 (if 
   (entmake
     (list
    (cons 0 "MTEXT")          ; Entity Type
    (cons 1 "Some Text Here")      ; Text String
    (cons 10 '(0.0 0.0 0.0))      ; Insertion Point
    (cons 40 0.25)              ; Text Height
    )
   )

   (princ "\nText Entity Created.")
   (princ "\nText Entity was NOT Created.")
   )
   (princ)
)

 

Solution
For entities such as MTEXT that were created after AutoCAD R12, you will need to add the Entity SubClass Markers, group code 100, for this to work:

 (defun CreateMtext ()

 (if 
   (entmake
     (list
    (cons 0 "MTEXT")       ; Entity Type
    (cons 100 "AcDbEntity")    ; 100 Entity Code
    ;(cons 8 "DIM")         ; The Layer
    (cons 100 "AcDbMText")       ; 100 Entity Code
   
     ; For Other Formatting Codes See the:
     ; ActiveX and VBA Developer's Guide ->
     ; Chapter 4 -- Creating and Editing AutoCAD Entities ->
     ; Adding Text to Drawings ->
     ; Using Multiline Text (Mtext) ->
     ; Formatting Multiline Text
   
    (cons 1 "\\S100^200")       ; Stacked Text
    (cons 10 '(0.0 0.0 0.0))   ; Insertion Point
    )
   )


   (princ "\nMtext Entity Created.")
   (princ "\nMtext Entity NOT Created.")
   )
   (princ)
)
(princ "\nCreateMtext loaded, type (CreateMtext) to run.")
(princ)

Using Plant3d Project.xml file to obtain data

by Fenton Webb

If you are new to Plant3d, it’s tempting to quickly obtain project data directly from the Project.xml file.

The Project.xml file is an internal project file that should not really be used to extract Plant data. You should always use the API's because the XML file format can change from release to release.

Take, for instance, obtaining the list of P&ID drawings in AutoCAD P&ID. In 2011, you could

1) Read the Project.xml…

<ProjectPart name="PnId" fileName="C:\Fenton\Projects\PnID\Test ISO\PnIdPart.xml" relativeFileName="PnIdPart.xml" uncFileName="\\Fenton\Projects\PnID\Test ISO\PnIdPart.xml" />

2) Then Use the "relativeFileName" value to locate the "PnIdPart.xml" file.
3) Open the "PnIdPart.xml" file and search for the XML block named "<PnpDrawingFiles>"
4) Finally, inside the "<PnpDrawingFiles>" block, all the project drawing files are listed.

However, in P&ID 2013 these elements don’t exist anymore. This is because we had issues with multi-user support, so we moved the file list into the DCF.

The correct way to obtain a list of P&ID DWG files is to use the API

Autodesk.ProcessPower.ProjectManager.Project.GetPnPDrawingFiles()

Zooming to drawing extents

By Virupaksha Aithal

Simple and direct method to zoom the drawing to its extents is use the ActiveX API “ZoomExtents” as shown in below code.

VB.NET

        <CommandMethod("TestZoomExtent")> _

        Public Sub TestZoomExtent()

            'AcadApplication has a function to zoom extent

            Dim acadApp As Object = Application.AcadApplication

            acadApp.ZoomExtents()

        End Sub

C#

[CommandMethod("zoomExtentTest")]

public static void zoomExtentTest()

{

    //using InvokeMember to support .NET 3.5

    Object acadObject = Application.AcadApplication;

    acadObject.GetType().InvokeMember("ZoomExtents",

                BindingFlags.InvokeMethod, null, acadObject, null);

}