How to call Active Reports 2.0 com component from .net?

I registered the Active Reports dll, arpro2.dll using regsvr32 Generating an interop assembly for Active Reports results in a servar fault: Main.cs

using System.Diagnostics;
using DDActiveReports2;

namespace TestActiveReports
{
    internal class Program
    {
        private static void Main()
        {
            var r = new ActiveReportClass();
            r.LoadLayout(@"C:\temp\RPTCUM20F.rpx");
            var s = r.Sections;
            Debug.Assert(s.Count() > 0);
        }
    }
}

.csproj:

<COMReference Include="DDActiveReports2">
  <Guid>{A7973091-BC64-4F16-84D4-A4BE059B4927}</Guid>
  <VersionMajor>2</VersionMajor>
  <VersionMinor>0</VersionMinor>
  <Lcid>0</Lcid>
  <WrapperTool>tlbimp</WrapperTool>
  <Isolated>False</Isolated>
  <EmbedInteropTypes>True</EmbedInteropTypes>
</COMReference>

The project is set to build to x86, so bitness is, I think, no issue.

An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in TestActiveReports.exe

Additional information: The server threw an exception. (Exception from HRESULT: 0x80010105 (RPC_E_SERVERFAULT))

DebugDiag reveals a Win32 access violation exception being thrown

However writing this stub wrapper in vb6, compiling it to a COM component, then referencing this COM component in .NET works:

VERSION 1.0 CLASS
BEGIN
  MultiUse = -1  'True
  Persistable = 0  'NotPersistable
  DataBindingBehavior = 0  'vbNone
  DataSourceBehavior  = 0  'vbNone
  MTSTransactionMode  = 0  'NotAnMTSObject
END
Attribute VB_Name = "VbActiveReport"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = True
Private ar As activeReport

Option Explicit


'CONSTRUCTOR

Private Sub Class_Initialize()
Set ar = New activeReport
End Sub


'DECONSTRUCTOR

Private Sub Class_Terminate()
Set ar = Nothing
End Sub


'PROPERTIES

Public Property Get Sections() As Sections
    Set Sections = ar.Sections
End Property


'METHODS

Public Sub LoadLayout(path As String)
ar.LoadLayout path
End Sub

Writing a VB6 wrapper for all the functions and types feels both dirty. Also, after half a day fiddling with a home brewed generator, it doesn't sound as trivial as I first thought.

Why does .NET => COM compiled from VB6 => active reports work, while .NET => active reports fails?

Edit: This is the event log entry

Faulting application name: TestActiveReports.vshost.exe, version:12.0.30723.0, time stamp: 0x53cf4fe6
Faulting module name: arpro2.dll, version: 2.5.0.1322, time stamp: 0x4d252d15
Exception code: 0xc0000005
Fault offset: 0x0002b2a0
Faulting process id: 0x2368
Faulting application start time: 0x01d1b9b4eadc0f51
Faulting application path: C:\Users\myuser\Documents\Visual Studio 2013\Projects\TestActiveReports\TestActiveReports\bin\Debug\TestActiveReports.vshost.exe
Faulting module path: C:\temp\Active reports\arpro2.dll
Report Id: 2980b2a1-25a8-11e6-82c6-c4d987b41689

Not much more info in here :(

Turns out the report files, .rpx, contain embedded VB6 code. I suspect this is the reason why going through a VB wrapper makes a difference. LoadLayout must be evaluating the VB6 code in the rpx, so it needs the VB runtime and/or libraries.

Turns out, a VB wrapper to forward function calls was not even necessary. A VB factory for the ActiveReport object does suffice.

Function CreateReport () As ActiveReport
    Set CreateReport = new ActiveReport
End Function

Having an intermediate factory com component with a single function within a single module is just good enough for now - very little work, no real need to maintain.

A possibly cleaner way would be to just load the VB runtime & libraries as references and expose them to the ActiveReports object created by newing up the Interop type. Trouble is, I didn't figure out how to do it.