Through the Interface

28 responses to “AutoCAD .NET version of the ObjectARX BlockView sample”

1. 

   Tony Tanzillo

   June 13, 2008 at 10:57 pm

   Hi Kean.

   The failure that happens when Visual Studio tries to load the AutoCAD interop assemblies is a fairly common problem.

   One way it can be dealt with is through the use a simple test that tells if the code is running in the Visual Studio IDE, or in AutoCAD.

   For that I generally use System.Process to get the name of the current process, and if it is 'acad', then I know its safe to call AutoCAD APIs.

   In this case, a test like that can be used to skip the contstruction of the preview control, when the code is running in the IDE.

   Reply
2. 

   Kean Walmsley

   June 16, 2008 at 2:32 pm

   Great suggestion - thanks, Tony.

   Kean

   Reply
3. 

   Fernando Malard

   October 5, 2009 at 5:34 pm

   Kean,

   Do you recommend the same approach to use the BlockView inside a WPF form?

   I remember Fenton have talked something about it on AU2008 class...not sure.

   Fernando.

   Reply
4. 

   Kean Walmsley

   October 5, 2009 at 7:50 pm

   Fernando,

   I don't know of any specific issues: I do recommend giving it a try and letting us know if you hit any issues. 🙂

   Regards,

   Kean

   Reply
5. 

   Jernej

   December 11, 2009 at 2:52 pm

   Hello,
   Is this a stable control? I have tried working with it in .NET but it is working very unstable. Maybe I don't know how to work with it. Are there any other .NET examples beside the one above. I have also used this control in c++ ObjectARX and there was no problem.

   Reply
6. 

   Kean Walmsley

   December 13, 2009 at 2:49 pm

   Hi Jernej,

   I don't know of any stability issues, but then I haven't integrated this control into any serious application.

   Please submit any issues you hit to the ADN team, and we'll take a look.

   Thanks,

   Kean

   Reply
7. 

   S. Jaisimha

   January 1, 2010 at 3:35 pm

   Hi Kean,

   If I use the GsPreviewCtrl in my form, the ViewToBeDestroyed event is not fired when the form is closed. This leads to a Fatal Error crash after a couple of minutes of using the form. I have done everything as in your BlockView sample, but nothing doing.

   The BlockView sample fires the event successfully and closes gracefully. Any idea what I am missing?

   Thanks and a very happy New Year to you and all readers of this blog.

   Reply
8. 

   Kean Walmsley

   January 4, 2010 at 9:59 pm

   Happy New Year to you, too!

   As this isn't my code (and you're an ADN member) I suggest posting your question via the ADN site.

   You're likely to get a better response from them.

   Kean

   Reply
9. 

   Mohammad Afghari

   July 7, 2010 at 6:23 pm

   Is there any way to add select
   entity feature to this component?

   Reply
10. 

    Cattoor Bjorn

    May 25, 2011 at 11:05 pm

    Thanks for this fantastic code!I really appreciate it.

    Reply
11. 

    Chuck Wilbur

    November 10, 2011 at 11:20 pm

    I came looking for a simple way to create a thumbnail bitmap from a block reference and wound up with something generic enough I thought more people might find it useful.

    Using BlockView and a little of the render to file stuff at keanw.com/2007/04/rendering_autoc.html , I got my bitmap created, but I also came up with an architecture that lets you load the control in the designer without crashing Visual Studio. Instead of inheriting a PreviewCtrl class that the designer can't handle, I created a wrapper class in 100 lines of code that takes a plain old Panel object and hooks in the view/model/device and an OnPaint event to redraw the view.

    The code for the class (which can be dropped into any old ACAD addon project) looks like this:

    ********************************************
    using System;
    using System.Collections.Generic;
    using System.Drawing;
    using System.Linq;
    using System.Text;

    using Autodesk.AutoCAD.ApplicationServices;
    using Autodesk.AutoCAD.DatabaseServices;
    using Autodesk.AutoCAD.Geometry;
    using Autodesk.AutoCAD.GraphicsSystem;

    namespace SNS.DesignData.Draw.Forms
    {
    public class EntityViewManager : IDisposable
    {
    View _view = new View();
    Device _device;
    Model _model;
    System.Windows.Forms.Panel _control;

    static Manager GraphicsManager
    {
    get { return Application.DocumentManager.MdiActiveDocument.GraphicsManager; }
    }

    public EntityViewManager(Entity ent, System.Windows.Forms.Panel control)
    {
    _device = GraphicsManager.CreateAutoCADDevice(control.Handle);
    _device.OnSize(control.Size);
    _device.BackgroundColor = control.BackColor;
    _device.Add(_view);
    _model = GraphicsManager.CreateAutoCADModel();
    _view.Add(ent, _model);
    // TODO: Figure out why line weight is not displayed

    SetView(_view, ent);

    // TODO: Figure out why text from overrides is not displayed
    _view.Update();

    _control = control;
    _control.Paint += control_Paint;
    }

    public static Bitmap GetBitmap(Entity ent, Size size, Color backgroundColor)
    {
    Bitmap result = new Bitmap(size.Width, size.Height);

    using (View view = new View())
    using (Device device = GraphicsManager.CreateAutoCADOffScreenDevice())
    using (Model model = GraphicsManager.CreateAutoCADModel())
    {
    view.Add(ent, model);
    device.Add(view);
    device.OnSize(size);
    device.BackgroundColor = backgroundColor;
    device.DeviceRenderType = RendererType.FullRender;

    SetView(view, ent);

    result = view.RenderToImage();
    device.EraseAll();
    }
    return result;
    }

    static void SetView(View view, Entity ent)
    {
    Extents3d viewExtents = ent.GeometricExtents;
    Point3d boxCenter = viewExtents.MinPoint + 0.5 * (viewExtents.MaxPoint - viewExtents.MinPoint);
    Point3d eye = boxCenter + Vector3d.ZAxis;
    double xMax = Math.Abs(viewExtents.MaxPoint.X - viewExtents.MinPoint.X + 1);
    double yMax = Math.Abs(viewExtents.MaxPoint.Y - viewExtents.MinPoint.Y + 1);
    view.SetView(eye, boxCenter, Vector3d.YAxis, xMax, yMax);
    }

    void control_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
    {
    _view.Invalidate();
    _view.Update();
    }

    #region IDisposable Members

    public void Dispose()
    {
    _control.Paint -= control_Paint;
    _control.Invalidate();
    _device.Erase(_view);
    _view.EraseAll();
    _model.Dispose();
    _view.Dispose();
    _device.Dispose();
    }

    #endregion
    }
    }
    ********************************************

    To use this to render an entity in a dialog temporarily I just do a using (var view = new EntityViewManager(ent, controlPreview)), and when I leave the using clause the view is cleared and the placeholder control reverts to normal. ent is any ACAD database object type and controlPreview is the Panel control hosted in your dialog.

    For a longer-lived preview the dialog will probably need an EntityViewManager member variable, created when the dialog is displayed and disposed when the dialog is closed. I did this in a modeless palette and had to make sure to also dispose of the EntityViewManager upon notification that the current document was closing because by the time the palette was destroyed the current document was gone and the model/view/device couldn't be disposed cleanly.

    The static GetBitmap method is pretty straightforward, tacked onto this class to make use of the common view/extent/eye setup code.

    You may notice the two TODOs. If the entity passed in is a Polyline with Lineweight set thick, the control only displays a thin line. I keep expecting to find a ShowLineWeight property on one of the view/model/device objects somewhere, but so far no luck.

    The more complicated TODO is because I'm also playing with overrules to draw some text and extra lines next to polylines with certain xdata (see keanw.com/overrules/ ). If I pass one of these lines to the wrapper, the extra lines show up but the text does not. I'm completely stumped on this behavior.

    Reply
12. 

    Kean Walmsley

    November 11, 2011 at 10:44 pm

    Thanks for posting this, Chuck.

    I'll take a closer look, when I get the chance - at first glance it looks very interesting.

    Kean

    Reply
13. 

    Alex

    March 22, 2012 at 7:17 am

    Hi Kean:

    I've downloaded the code.
    I run the code in vs2008 and cad2010.
    When I use the commnad add an entity to the database after I open a dwg file ,there is some wrong occur.It's tip eWrongDatabase.

    I've changed the code like that:
    original code ://next add it to the current space
    //using (BlockTableRecord curSpace = mPreviewCtrl.mCurrentDwg.CurrentSpaceId.Open(OpenMode.ForWrite) as BlockTableRecord)
    // curSpace.AppendEntity(sphere);

    replaced code:
    ObjectId entId;
    Database pDb = new Database();
    pDb=mPreviewCtrl.mCurrentDwg;
    if (pDb != null)
    {
    using (Transaction trans = pDb.TransactionManager.StartTransaction())
    {
    try
    {
    BlockTable bt = (BlockTable)trans.GetObject(pDb.BlockTableId, OpenMode.ForRead);
    BlockTableRecord btr = (BlockTableRecord)trans.GetObject(bt[BlockTableRecord.ModelSpace], OpenMode.ForWrite);

    entId = btr.AppendEntity(sphere);
    trans.AddNewlyCreatedDBObject(sphere, true);
    trans.Commit();
    }
    catch (System.Exception ex)
    {
    MessageBox.Show(ex.ToString());
    }

    }

    Reply
14. 

    Kean Walmsley

    March 22, 2012 at 12:45 pm

    Hi Alex,

    I'm afraid I can't provide support for your extensions to this code. I suggest you post your question to ADN or the AutoCAD .NET Discussion Group.

    You seem to be mixing Open/Close (although I don't see a Close() call) with transactions - a very bad idea. Hopefully someone on the discussion group will be able to help.

    Regards,

    Kean

    Reply
15. 

    alexb

    August 6, 2012 at 10:28 pm

    Hi Kean:

    I am intersted in a similar functionality in a .exe program running external to Acad (with Acad installed and - possibly - running).
    Is it possible for such a program to use the Acad .NET API to acomplish this?
    Thanks
    alex
    N.B. No relation to the post above 🙂

    Reply
16. 

    Kean Walmsley

    August 6, 2012 at 10:46 pm

    Hi Alex,

    How about this?

    keanw.com/2008/03/embedding-autoc.html

    Cheers,

    Kean

    Reply
17. 

    alexb

    October 1, 2012 at 7:31 am

    Hi Tony

    Could you elaborate on that? Where do you put the checking code?
    I can't seem to make it work.

    Thanks

    alex

    Reply
18. 

    Anonymoose

    October 26, 2012 at 7:17 pm

    Explained here:

    forums.autodesk.com/t5/NET/Blockview-NET/m-p/3675470#M31703

    Reply
19. 

    Anonymoose

    October 28, 2012 at 6:37 pm

    You can find a revised/refactored version of the BlockView.NET sample here:

    forums.autodesk.com/t5/NET/Blockview-NET/m-p/3676654#M31712

    The refactored code fixes the problems with opening the BlockViewDialog in the designer, so you don't have to resort to using the workaround suggested in this blog post.

    Reply
20. 

    Farrukh

    March 19, 2013 at 5:07 pm

    Hi Kean,
    Thanks for this nice piece of code. I just wonder if we can
    doc.SendStringToExecute("(command ""zoom"" ""e"")" + '\r' + '\n', true, false, false);

    I'm just trying to call AutoCAD's built-in Zoom Extents command in BlockView.

    Is that possible?

    Best regards
    Farrukh

    Reply
21. 

    Farrukh

    March 19, 2013 at 5:10 pm

    And is there any way to simply generate bmp/png/jpg from dwg files? I need to show a preview of selected dwg from a ListView dialog.

    Thanks

    Reply
22. 

    Kean Walmsley

    March 19, 2013 at 5:21 pm

    Hi Farrukh,

    No, you can't target the block view window with AutoCAD commands: look at the approach used by the Zoom option, instead.

    This may be of help:

    keanw.com/2007/04/taking_a_snapsh_1.html

    You might also find something on the ADN DevBlog, if I remember correctly (although I couldn't find the exact thing):

    adndevblog.typepad.com/autocad

    Regards,

    Kean

    Reply
23. 

    Farrukh

    March 20, 2013 at 3:37 pm

    Kean,
    Yes, I tried that approach, but its not working as standard Zoom Extents in Top view is doing. That makes me to call the Lisp methodology.

    I'm trying to set two things:
    Permanently set TOP view
    Zoom Extents.

    Thanks much for all help.

    Regards

    Reply
24. 

    Stephan

    November 15, 2013 at 7:56 am

    Has anyone seen a VB.Net version of this code?
    I don't have the world of experience in C# and would to have a read in a different format.

    Thanks.

    Reply
25. 

    Stephan

    December 12, 2013 at 8:14 am

    Dispose of the Control on Close fixed this issue for me. (rightly or wronly)

    Reply
26. 

    swaywood

    December 16, 2015 at 1:30 pm

    Hi Kean:

    when i change to acad19.0,

    the namespace Autodesk.AutoCAD.GraphicsSystem
    {
    [Wrapper("AcGsView")]
    public class View : DisposableWrapper
    do not have the 'Viewport' property

    how to change the code?

    the error line is on GsPreviewCtrl.cs line 174 System.Drawing.Rectangle view_rect = mpView.Viewport;

    Reply
    1. 

       Kean Walmsley

       December 17, 2015 at 1:14 pm

       Hi there,

       Please take a look at the updated BlockView project for AutoCAD 2015 onwards:

       adndevblog.typepad.com/autocad/

       Regards,

       Kean

       Reply
27. 

    Vrender Company

    July 16, 2017 at 5:58 am

    uploads.disquscdn.c...

    Reply