Exception Error

[massretailers]

Dear Experts,

Here i am trying to open dwg file from revit api below is my code and exception error,

using System.Diagnostics;
using Autodesk.Revit.ApplicationServices;
using System.Text;
using Autodesk.Revit.Attributes;
using Autodesk.Revit.DB;
using Autodesk.Revit.UI;
using Autodesk.Revit.UI.Selection;
using System.Threading.Tasks;
using System.Reflection;
using Autodesk.Revit.DB.Architecture;
using System;
using AutoCAD;
using System.Runtime.InteropServices;
using System.IO;
using Autodesk.AutoCAD.ApplicationServices;
//using Autodesk.AutoCAD.Interop;
using Autodesk.AutoCAD.Runtime;
//using Autodesk.AutoCAD.ApplicationServices;


namespace cad_open
{
    [Autodesk.Revit.Attributes.Transaction(Autodesk.Revit.Attributes.TransactionMode.Manual)]
    public class main : IExternalCommand
    {
        private AcadApplication AcadApp = default(AcadApplication);

       
        public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
        {
            UIApplication uiapp = commandData.Application;
            UIDocument uidoc = uiapp.ActiveUIDocument;
            Autodesk.Revit.ApplicationServices.Application app = uiapp.Application;
            Autodesk.Revit.DB.Document doc = uidoc.Document;
            AcadApp = new AcadApplication();
            //AcadApp = (AcadApplication)Marshal.GetActiveObject("AutoCAD.Application");
            AcadApp.Visible = true;
            
            // AcadApp.ActiveDocument.SendCommand("_MYCOMMAND ");
     
            try
            {
                using (Transaction mytrans = new Transaction(doc, "Transcation"))
                {
                    try
                    {
                        DocumentCollection doccol = Autodesk.AutoCAD.ApplicationServices.Core.Application.DocumentManager;
                        doccol.Open(@"C:\ProgramData\Autodesk\123.dwg", false);
                        AcadApp.ZoomExtents();
                    }
                    catch (Autodesk.AutoCAD.Runtime.Exception ex)
                    {
                        TaskDialog.Show("Error1", ex.Message);
                    }
                }
            }
            catch (Autodesk.AutoCAD.Runtime.Exception ex)
            {
                TaskDialog.Show("Error1", ex.Message);
            }
            
            return Result.Succeeded;
        }
    }

Regards

Mass.R 

[matthew_taylor]

Hi @massretailers,

I'm no expert in this field, but here are a couple of things to check (these are for AutoCAD 2013, so may be a touch out of date):

• Your project should have ComVisible set to TRUE.
• References to:
  • Autodesk.AutoCAD.Interop
  • Autodesk.AutoCAD.Interop.Common
• Comment out all code except opening/getting AutoCAD. Once you have that running, add further steps.

Here's the quick and dirty (VB.NET) code I have used:

Private progID As String = "AutoCAD.Application.19"
Try
            acApp = DirectCast(GetObject(, progID), _
			Autodesk.AutoCAD.Interop.AcadApplication)
Catch ex As System.Exception
            Try
                 Dim acType As Type = Type.GetTypeFromProgID(progID)
                 acApp = DirectCast(CreateObject(progID), _
			   Autodesk.AutoCAD.Interop.AcadApplication)

            Catch ex2 As System.Exception
                  MessageBox.Show((Convert.ToString( _
                            "Cannot create object of type """) & progID) + """")
            End Try
End Try

Cheers,

-Matt