C#

[Guid("47C976E0-C208-4740-AC42-41212D3C34F0"),
InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
public interface MyCom_Events
{
   // [DispID(1)]
    void OK();
}


[Guid("368C19C3-A726-49b5-A2D8-482680ADDA1D")]
public interface IMyCom
{
    int Add(int a, int b);
    void OnOK();
}
[Guid("498627AF-BCD0-4a1f-95E4-739953847B60"),
ClassInterface(ClassInterfaceType.None),
ProgId("Test.MyCom"),
ComSourceInterfaces(typeof(MyCom_Events))]
public class MyCom : IMyCom
{
    #region IMyCom Members

    public int Add(int a, int b)
    {
        return a + b;
    }

    public void OnOK()
    {
        if (OK != null)
            OK();
    }

    public delegate void OKHander();

    public event OKHander OK;

    #endregion
}

CoInitialize(NULL);//NULL换成0也可以
            cscomtest::IMyComPtr pIMyCom(__uuidof(cscomtest::MyCom));
            cout<<"out:"<<pIMyCom->Add(1,2)<<endl;
                            //How to attach a method？？？？？
pIMyCom->OnOK();
            CoUninitialize();

private Image mybtn;

public Image MyBtn{
    get{return = mybtn;}
    set{mybtn = value;}
}

public static void SetButtonImage(string imgPath){
    MyBtn = new Bitmap(imgPath);
}

[DllImport( "DCamLIB.dll" )]
private unsafe static extern bool DcamCapture( ushort* imageBuffer, Int32 bufferSize );

using (frmpopupEmailRecipient popupVerifyEmailRecipients = new frmpopupEmailRecipient(ref EmailTo, ref EmailCC))
           {
               // passing this in ShowDialog will set the .Owner
               // property of the child form
               popupVerifyEmailRecipients.ShowDialog(this);
           }