Working with Multi-threading COM object in STA Thread

Question

I am trying to use the third party com object in my .net application.

By this com object I am trying to connect to mssql database.

The com object works only in MTA thread. The "ThreadingModel" value of the object in registry is "Apartment".

When I tried to work with object in Console Application - connection successes. When I change project type to Windows Application - connection fails (com object method returns message "-2147023550:OLE DB error occured. Code 80070542h"). When I add STAThread attribute to the Main method of the console application - connection fails.

I have tried to call my com object from another thread with MTA apartment, but connection also fails.

I'm trying to create my com object by this code:

var result = ComSecurity.CoInitializeSecurity(
                IntPtr.Zero,
                -1,
                IntPtr.Zero,
                IntPtr.Zero,
                RpcAuthnLevel.None,
                RpcImpLevel.Impersonate,
                IntPtr.Zero,
                EoAuthnCap.None,
                IntPtr.Zero);

var serverApplication = Activator.CreateInstance(Type.GetTypeFromProgID("LoodsmanServerApplication.MainSystem")) as IMainSystem;

...

public enum RpcAuthnLevel
    {
        Default = 0,
        None = 1,
        Connect = 2,
        Call = 3,
        Pkt = 4,
        PktIntegrity = 5,
        PktPrivacy = 6
    }

public enum RpcImpLevel
    {
        Default = 0,
        Anonymous = 1,
        Identify = 2,
        Impersonate = 3,
        Delegate = 4
    }

    public enum EoAuthnCap
    {
        None = 0x00,
        MutualAuth = 0x01,
        StaticCloaking = 0x20,
        DynamicCloaking = 0x40,
        AnyAuthority = 0x80,
        MakeFullSIC = 0x100,
        Default = 0x800,
        SecureRefs = 0x02,
        AccessControl = 0x04,
        AppID = 0x08,
        Dynamic = 0x10,
        RequireFullSIC = 0x200,
        AutoImpersonate = 0x400,
        NoCustomMarshal = 0x2000,
        DisableAAA = 0x1000
    }

[DllImport("ole32.dll")]
public static extern int CoInitializeSecurity(IntPtr pVoid, int
            cAuthSvc, IntPtr asAuthSvc, IntPtr pReserved1, RpcAuthnLevel level,
            RpcImpLevel impers, IntPtr pAuthList, EoAuthnCap dwCapabilities, IntPtr
            pReserved3);

Is there any way to use MTA COM object from STA thread?

It would be much easier if you would specify what exactly "doesn't work" means. what errors do you get? what do you expect to see? I have a feeling that your problem is not related to threading model. — Zdeslav Vojkovic
Forcing MTA has a side-effect, it forces the data provider to run on another thread. The error is an obscure one, ERROR_BAD_IMPERSONATION_LEVEL. There's something wrong with the user account you use on your main thread, the dbase provider is unhappy with it. I have to guess that you left the important code out of the snippet, something to do with impersonation. — Hans Passant
Well, close enough guess, you are using RpcImpLevel.Impersonate. Without any explanation why you do this, the obvious answer is "don't do that". — Hans Passant

user1878599 user1878599 · Accepted Answer · 2014-04-02T12:23:44

You should use delegation level instead of impersonation. MTA/STA has nothing to do with it.

var result = ComSecurity.CoInitializeSecurity(
                IntPtr.Zero,
                -1,
                IntPtr.Zero,
                IntPtr.Zero,
                RpcAuthnLevel.None,
                RpcImpLevel.Delegate,
                IntPtr.Zero,
                EoAuthnCap.None,
                IntPtr.Zero);

Working with Multi-threading COM object in STA Thread

1 Answers