extending WPF/Avalon/XAML - webcam preview [extending WPF/Avalon/XAML - webcam preview]

cosminb — Sun, 26 Mar 2006 09:25:09 GMT

Hello C9ers,

I'm having some trouble figuring out how to do this: I've developed a camera library in C++/CLI which I use further in C# apps. After making it accessible to Windows Forms and Direct3D, I want to give Avalon/WPF a try, but this is where I got a bit stuck (lack of proper information). As you can see from the thread's title, I want to achieve
the same functionality that currently is given by MediaElement/MediaPlayer. I want to be able to output my webcam preview video to any Visual element in WPF. How do I do that? Do I need to subclass MediaElement? Or MediaPlayer? Or something else. And how do I customize it? I hope someone has an answer to this really soon, I'm
betting my final year project on this.

Thanks in advance,

Cosmin.

P.S. Also, I want to know if C++/CLI can be used to subclass the controls, or it has to be done in C#.

I've tried several places to get this info, noone seems to care... I hope C9 will.

in reply to extending WPF/Avalon/XAML - webcam preview

Writing a managed version of ICreateDevEnum [Writing a managed version of ICreateDevEnum]

cosminb — Sat, 11 Mar 2006 20:10:24 GMT

I have the following interface from "strmif.h" (DirectShow stuff):

    MIDL_INTERFACE("29840822-5B84-11D0-BD3B-00A0C911CE86")
    ICreateDevEnum : public IUnknown
    {
    public:
        virtual HRESULT STDMETHODCALLTYPE CreateClassEnumerator(
            /* [in] */ REFCLSID clsidDeviceClass,
            /* [out] */ IEnumMoniker **ppEnumMoniker,
            /* [in] */ DWORD dwFlags) = 0;

    };

I have found it described in C# like this (in a project called DShow.NET):

    [ComVisible(true), ComImport,
    Guid("29840822-5B84-11D0-BD3B-00A0C911CE86"),
    InterfaceType( ComInterfaceType.InterfaceIsIUnknown )]
public interface ICreateDevEnum
{
        [PreserveSig]
    int CreateClassEnumerator(
        [In]                                            ref Guid            pType,
        [Out]                                        out UCOMIEnumMoniker    ppEnumMoniker,
        [In]                                            int                    dwFlags );
}

The generated MSIL for the function is:

.method public hidebysig newslot abstract virtual
        instance int32 CreateClassEnumerator([in] valuetype [mscorlib]System.Guid& pType,
                                              [out] class [mscorlib]System.Runtime.InteropServices.UCOMIEnumMoniker& ppEnumMoniker,
                                              [in] int32 dwFlags) cil managed preservesig
{
} // end of method ICreateDevEnum::CreateClassEnumerator

And now my question is: How to represent this interface in C++/CLI? I use VS2005, and tried several times, but it doesn't compile. I am stuck on the IEnumMoniker parameter, don't know how to declare it.

Does anyone have an idea on how to write this interface in C++/CLI, so that I am able to cast the COM server 'SystemDeviceEnum' to the interface 'ICreateDevEnum'?

Thanks,
Cosmin

in reply to Writing a managed version of ICreateDevEnum

Entries for cosminb

extending WPF/Avalon/XAML - webcam preview [extending WPF/Avalon/XAML - webcam preview]

Writing a managed version of ICreateDevEnum [Writing a managed version of ICreateDevEnum]