ApprenticeServer as Windows Service

[DynamicObjects]

Hello Autodesk and forum

I am attempting to retrieve the thumbnails for part files like this ...

// use ApprenticeServerComponent to run In-Process to obtain thumbnail
   oApprenticeServerDoc = oApprenticeApp.Open(component.LocalFilenameAndPath);  

// obtain the thumbnail image
  Console.WriteLine("attempting to get thumbnail for " + oApprenticeServerDoc.FullFileName);
  stdole.IPictureDisp thumbnailIPD = oApprenticeServerDoc.Thumbnail;

The final line fails when running in the WindowsService. ...

The above code sits in a method that I use in a Standard Windows Forms App exe, and also in my process that is started and run as a windows service.

It works well for the WindowsFormsApp.

The final line above fails when running in the WindowsService with the exception ... 

Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED)) at System.RuntimeType.ForwardCallToInvokeMember(String memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData) at Inventor.ApprenticeServerDocument.get_Thumbnail()

Is there an issue with running ApprenticeServer as a Windows Service --- can anyone confirm whether this is the likely cause of the above failure??

Regards

Dan

[YuhanZhang]

Is that an out-of-process call when you run it in Windows Service? Microsoft does not allow to pass the IPictureDisp object across the processes. Below is a post demonstrates this:

http://modthemachine.typepad.com/my_weblog/2010/03/document-thumbnails-and-button-icons.html

So if your work is to call ApprenticeServer to get thumbnail in process it should work(otherwise there would be a problem), if you run it as an out-of-process then you need to find a workaround. Brian provided a workaround for this in the above post, please let me if that works for you.

[DynamicObjects]

It is always in-process in both our scenarios because we are using ApprenticeServerComponent - which runs in-process to our application. That is the whole point of using ApprenticeServerComponent 🙂

[YuhanZhang]

Then the failure happens to specific Inventor document or all documents? Can you share us reproducible steps so we can look into where the problem happens?

[DynamicObjects]

Hi Rocky,

I was in the process of making the smallest possible WindowsService to send to you to reproduce the problem when i found this error which makes me think it may not be related to whether the exe is a service or not.

I think i am not understanding something more fundamental with using ApprenticeServerComponent -- here is my short code and it stops on line 24 (line in red) with COM exception -- which i don't understand why it is using COM for ApprenticeServerComponent???  -- i thought the whole point was that ApprenticeServerComponent runs in-process to my app??

using System;
using InventorApprentice;

namespace SimpleThumbnailSaver
{
    public class Program
    {
        public static void Main(string[] args)
        {
            // do my stuff
            DoMyStuff();
        }

        public static void DoMyStuff()
        {
            // get ApprenticeServerComponent
            ApprenticeServerComponent apprentice = new ApprenticeServerComponent();

            // get the thumbnail from my test file
            string filename = @"C:\Temp\TestPart.ipt";
            ApprenticeServerDocument document = apprentice.Open(filename);
            Console.WriteLine("opened {0}",document.FullFileName);
            stdole.IPictureDisp thumbnail;
            thumbnail = document.Thumbnail;

            //// convert the thumbnail to an image
            //....
        }
    }
}

Does this code run for you?  Or does it also stop at the red line with an error?

Regards

Dan.

[DynamicObjects]

I should add - that the method DoMyStuff() works fine in a Windows Form App, but fails above as described as a Windows Console App.

[DynamicObjects]

i should also clarify that if i transcribe the code to vb.net then i find that both the console app and the windows form app work... so i can only reproduce the error with c# when compiling as a console app or as a windows service. -- i am baffled !!

[DynamicObjects]

and here i've attached both the C# and VB versions of that very simple app...

[chandra.shekar.g · Accepted solution]

Hi @DynamicObjects,

As you mentioned in the previous post, C# code throws exception at thumbnail = document.Thumbnail; But, VB.net source code works fine and image will be saved.

So, a change request (INVGEN - 11322 - Failed at Document.Thumbnail using Apprentice Server in C#) is raised with engineering team.

Thanks and regards,

[DynamicObjects]

Thanks Chandra - could you add me to a list to be informed when the fix is available please?

[chandra.shekar.g]

Hi @DynamicObjects,

Once fix is solved. I will let you know.

Thanks and regards,

[Anonymous]

is this solved yet?

[chandra.shekar.g · Accepted solution]

@Anonymous,

After checking change request - 11322, it seems that it may be fixed in the upcoming version of Inventor.

Thanks and regards,

[chandra.shekar.g]

@Anonymous,

Issue has been fixed in Inventor 2020 with little changes in C# code as shown in below.

public class Program
    {
        // get ApprenticeServerComponent
        private static ApprenticeServerComponent apprentice = new ApprenticeServerComponent();
        [STAThread]
        private static void Main(string[] args)
        {
            // do my stuff
            DoMyStuff();
        }

        private static void DoMyStuff()
        {
            // get the thumbnail from my test file
            string filename = @"Path of file\Sample.ipt;
            ApprenticeServerDocument document = apprentice.Open(filename);
            Console.WriteLine("opened {0}",document.FullFileName);
            stdole.IPictureDisp thumbnail;
            thumbnail= document.Thumbnail;

            // convert the thumbnail to an image
            Image image = AxHostConverter.PictureDispToImage(thumbnail);

            // save the thumbnail image to the same folder using the next incremental number as a filename suffix
            filename = Path.GetDirectoryName(filename) + @"\" + Path.GetFileNameWithoutExtension(filename) + "_001.png" ;
            image.Save(filename, ImageFormat.Png);
            image.Dispose();
        }
    }

Note: Make sure that solution is built with x64 platform.

Thanks and regards,