Issues compiling in Windows 10

Question

I have identified an issue related to building apps that use C:\Windows\System32\CertEnroll.dll as a reference.

The following code works fine when compiled using VS 2015 on Windows 7 and then ran on a Windows 7 machine.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using CERTENROLLLib;

namespace CertTest
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                CX509PrivateKey key = new CX509PrivateKey();
                key.ContainerName = Guid.NewGuid().ToString();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
    }
}

When you try and compile this in Windows 10 and then try and run it on a Windows 7 machine, it throws the following error.

"Unable to cast COM object of type 'System.__ComObject' to interface type 'CERTENROLLLib.CX509PrivateKey'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{728AB362-217D-11DA-B2A4-000E7BBB2B09}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE))."

I have had several people here replicate it and I'd like to get more input before contacting Microsoft on what's going on here.

I guess my question is: Can anybody else confirm this or if it's confirmed they broke backward compatibilty?

Answer 1

These are the steps from Microsoft to resolve this issue

If you use Windows 10 solely as your build environment then the executable would run on downlevel OSes, however if you really just want to have a project that you can compile anywhere and run anywhere then the only solution is to create your own interop DLL that you include in the project folder. You would have to generate it on Windows 7 first and reference that DLL.

Tlbimp.exe CertEnroll_Interop c:\Windows\System32\CertEnroll.dll

This generates a CertEnroll_Interop.dll file that you can copy to your project folder and then browse to in your project. Of course you would need the using “using CertEnroll_Interop;” statement.

You can build the project on Windows 10 and have it run on Windows 7 and Windows 8.1 and any other combination.