topic Re: interop COM list all open DWG files from all running sessions in .NET Forum

interop COM list all open DWG files from all running sessions

Anonymous — Wed, 15 Aug 2018 13:00:19 GMT

New custom dev needed . Must be external, must run outside AutoCAD. How would I list all DWG files opened by the user - the user may have more than one session running . Only one version of AutoCAD will need to be supported per year.

Thx for your patience,

Kevin.

Re: interop COM list all open DWG files from all running sessions

FRFR1426 — Thu, 16 Aug 2018 15:00:53 GMT

You can query the Runtime Object Table (ROT) for that. Here, you can download an utility named RotView which show you what is currently in the table. There will be an entry for each document opened in AutoCAD.

The documentation of the Windows API can be found here.

Philippe has written a blog post which show how to enumerate the table in C# here.

Re: interop COM list all open DWG files from all running sessions

Anonymous — Mon, 20 Aug 2018 10:08:56 GMT

did you get the ROT to work ? I tried using the code from the blog - did not work for me, it only displayed one of two sessions : (

Re: interop COM list all open DWG files from all running sessions

Anonymous — Mon, 20 Aug 2018 10:23:45 GMT

Aha! i have some success ... thx Max .

Re: interop COM list all open DWG files from all running sessions

Anonymous — Mon, 20 Aug 2018 10:57:01 GMT

this worked for me - for now .. I just needed to list all DWG files opened in all sessions ... in the future I will need to add much more to edit DWG CAD objects ...

        [DllImport("ole32.dll")]
        private static extern void CreateBindCtx(int reserved, out IBindCtx ppbc);

        [DllImport("ole32.dll")]
        private static extern int GetRunningObjectTable(int reserved, out IRunningObjectTable prot);

        public void allopendwgfiles()
        {
            string msg1 = "...\r\n";
            if (GetRunningObjectTable(0, out IRunningObjectTable pprot) == 0)
            {
                pprot.EnumRunning(out IEnumMoniker ppenumMoniker);
                ppenumMoniker.Reset();
                var moniker = new IMoniker[1];
                while (ppenumMoniker.Next(1, moniker, IntPtr.Zero) == 0)
                {
                    CreateBindCtx(0, out IBindCtx ppbc);
                    moniker[0].GetDisplayName(ppbc, null, out string ppszDisplayName);
                    Marshal.ReleaseComObject(ppbc);
                    if (ppszDisplayName.ToLower().Contains(".dwg")) // // .DWT .DWS maybe ...
                    {
                        pprot.GetObject(moniker[0], out object ppunkObject);
                        msg1 = msg1 + ppszDisplayName + "\r\n";
                    }
                }
            }
            System.Windows.Forms.MessageBox.Show(msg1);
        }

Re: interop COM list all open DWG files from all running sessions

Anonymous — Mon, 20 Aug 2018 12:48:26 GMT

error ... unable to cast COM ... to interface type Autodesk.AutoCAD.interop.AcadApplication ...

In trying to go further ... error occurs in the cast line of the list of COM objects AcadApplication acApp = (AcadApplication)cs1 ... why? The properties of cs1 show that it is AutoCAD - what have I missed? (AutoCAD 2018 , AutoCAD.Application.22 ...

            openDWGset = new List<string>();
            List<object> CADsessionSet = new List<object>();
            if (GetRunningObjectTable(0, out IRunningObjectTable pprot) == 0)
            {
                pprot.EnumRunning(out IEnumMoniker ppenumMoniker);
                ppenumMoniker.Reset();
                var moniker = new IMoniker[1];
                while (ppenumMoniker.Next(1, moniker, IntPtr.Zero) == 0)
                {
                    CreateBindCtx(0, out IBindCtx ppbc);
                    moniker[0].GetDisplayName(ppbc, null, out string ppszDisplayName);
                    if (ppszDisplayName.ToLower().Contains(".dwg")) 
                    {
                        object ComObject;
                        pprot.GetObject(moniker[0], out ComObject);
                        if (ComObject is null)
                            continue;
                        CADsessionSet.Add(ComObject);
                    }
                    Marshal.ReleaseComObject(ppbc);
                }
            }
            foreach(object cs1 in CADsessionSet)
            {
                try
                {
                    AcadApplication acApp = (AcadApplication)cs1;
                    foreach (AcadDocument doc1 in acApp.Documents)
                    {
                        if (!openDWGset.Contains(doc1.Name))
                            openDWGset.Add(doc1.Name);
                    }
                }
                catch(System.Exception ex1) {
                    System.Windows.Forms.MessageBox.Show(ex1.Message);
                };
            }

Re: interop COM list all open DWG files from all running sessions

FRFR1426 — Mon, 20 Aug 2018 12:55:13 GMT

You need to cast cs1 to an AcadDocument, not an AcadApplication. The objects in the ROT are documents, not application.

Re: interop COM list all open DWG files from all running sessions

Anonymous — Tue, 21 Aug 2018 04:18:02 GMT

Thx Max!!! : )

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Runtime.InteropServices.ComTypes;
using Autodesk.AutoCAD.Interop;
namespace nsCADi
{
    public class cadinterop
    {
        [DllImport("ole32.dll")]
        private static extern void CreateBindCtx(int reserved, out IBindCtx ppbc);
        [DllImport("ole32.dll")]
        private static extern int GetRunningObjectTable(int reserved, out IRunningObjectTable prot);
        public void AllDWGbyROT(ref List<string> openDWGset)
        {
            openDWGset = new List<string>();
            List<object> COMDocSet = new List<object>();
            if (GetRunningObjectTable(0, out IRunningObjectTable pprot) == 0)
            {
                pprot.EnumRunning(out IEnumMoniker ppenumMoniker);
                ppenumMoniker.Reset();
                var moniker = new IMoniker[1];
                while (ppenumMoniker.Next(1, moniker, IntPtr.Zero) == 0)
                {
                    CreateBindCtx(0, out IBindCtx ppbc);
                    moniker[0].GetDisplayName(ppbc, null, out string ppszDisplayName);
                    if (ppszDisplayName.ToLower().Contains(".dwg")) 
                    {
                        object ComObject;
                        pprot.GetObject(moniker[0], out ComObject);
                        if (ComObject is null)
                            continue;
                        COMDocSet.Add(ComObject);
                    }
                    Marshal.ReleaseComObject(ppbc);
                }
            }
            foreach(object cd1 in COMDocSet)
            {
                try
                {
                    AcadDocument cdoc1 = (AcadDocument)cd1;
                    AcadApplication acApp = cdoc1.Application;
                    foreach (AcadDocument doc1 in acApp.Documents)
                    {
                        if (!openDWGset.Contains(doc1.FullName))
                            openDWGset.Add(doc1.FullName);
                    }
                }
                catch(System.Exception ex1) {
                };
            }
        }
    }
}