Re: .NET COM/ActiveX problem

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I added a test method that just showed a messagebox and took no params, and
it worked fine. So it has to do with my passing the struct in as a param.
Any thoughts?

"Steven" <sedison@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:%23xXSBvNcJHA.5976@xxxxxxxxxxxxxxxxxxxxxxx
I've followed some websites advice for creating an "ActiveX assembly" and
everything was going along fine until I ran into a problem. The
methods/properties aren't marshalling correctly. I have an interface:

[ComVisible(true), Guid("B3A60DA4-8F40-4336-87D6-66282A702AAC"),
InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
public interface IMyHostWnd
{
[DispId(1)]
VIEWSTATE MyState { get; set; }
[DispId(2)]
int MyCount { get; }
[DispId(3)]
bool GetMyType(int Index, ref Nullable<MY_TYPE> MyType);
[DispId(4)]
bool AddMyWindow(MY_TYPE MyType);
}

Then the impl:

[Guid("B3A60DA6-8F40-4336-87D6-66282A702AAC")]
[ComSourceInterfaces(typeof(IMyHostWndEvents))]
[ProgId("MyHost.MyHostWnd")]
public partial class MyHostWnd : UserControl, IMyHostWnd
{
[ComVisible(true)]
[DispId(4)]
public bool AddMyWindow(MY_TYPE MyType)
{
...
}

....
}

The struct passed in is defined as:

[ComVisible(true)]
//[MarshalAs(UnmanagedType.SafeArray)]
public struct MY_TYPE
{
[MarshalAs(UnmanagedType.LPStruct)]
public Guid Identifier;
public string Manufacturer;
public string Model;
[MarshalAs(UnmanagedType.LPStruct)]
public Guid MyMethod;
}

The problem is when I use it in my unmanaged app I get all sorts of
marshalling errors, like the methods aren't lining up correctly. One time
I'll get "invalid number of parameters", I'll tweak my DispIDs or move
some methods around, recompile and it'll say "member not found", or some
other error telling me they aren't lined up correctly. I look at the
object in the OLE-COM Object viewer, and everything seems to be laid out
correctly as it looks in my .NET assembly.

On my unmanaged/MFC side I'm doing this:

//.h
CWnd m_MyWnd;

//cpp - error checking removed for post simplicity
BOOL b = m_MyWnd.CreateControl(MyHost::CLSID_IMyHostWnd, NULL,
WS_TABSTOP|WS_VISIBLE, rect, this, WM_USER+1);

LPUNKNOWN pUnk = m_MyWnd.GetControlUnknown();
pUnk->QuerryInterface(MyHost::IID__MyHostWnd, (LPVOID*)&m_pIMyHost);
MyHost::MY_TYPE mt;
//populate mt then...
m_pIMyHost->AddMyWindow(mt); //gets scrambled on this func, thows
_com_error


It never makes it to the AddMyWindow impl., I can step in until the
_com_dispatch_method() where I can see the dipatch id matched my impl and
interface.

Thanks for any help/advise.

Steven



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