自定义ActiveX .NET控件在WinForms / WPF项目中无法识别

Question

I'm creating an ActiveX control library (.dll) in .NET to be used in Internet Explorer. It implements IObjectSafety and looks similar to this:

namespace ActiveXControl
{
    [ComVisible(true)]
    [InterfaceType(ComInterfaceType.InterfaceIsDual)]
    [Guid("ABA9D4C3-8166-440C-90C8-2FA6CD4C3C77")]
    interface ITestControl
    {
        string GetText();
    }

    [ComVisible(true)]
    [ClassInterface(ClassInterfaceType.None)]
    [Guid("0B3C1BB4-ED2C-4336-9E4C-72A908E74F51")]
    [ProgId("ActiveXControl.TestControl")]
    [ComDefaultInterface(typeof(ITestControl))]
    public class TestControl : UserControl, ITestControl, IObjectSafety
    {
        #region ITestControl

        public string GetText()
        {
            return "Foo";
        }

        #endregion

        #region IObjectSafety

        public enum ObjectSafetyOptions
        {
            INTERFACESAFE_FOR_UNTRUSTED_CALLER = 0x00000001,
            INTERFACESAFE_FOR_UNTRUSTED_DATA = 0x00000002,
            INTERFACE_USES_DISPEX = 0x00000004,
            INTERFACE_USES_SECURITY_MANAGER = 0x00000008
        };

        public int GetInterfaceSafetyOptions(ref Guid riid, out int pdwSupportedOptions, out int pdwEnabledOptions)
        {
            ObjectSafetyOptions m_options = ObjectSafetyOptions.INTERFACESAFE_FOR_UNTRUSTED_CALLER | ObjectSafetyOptions.INTERFACESAFE_FOR_UNTRUSTED_DATA;
            pdwSupportedOptions = (int)m_options;
            pdwEnabledOptions = (int)m_options;
            return 0;
        }

        public int SetInterfaceSafetyOptions(ref Guid riid, int dwOptionSetMask, int dwEnabledOptions)
        {
            return 0;
        }

        #endregion
    }
}

When I create a .cab out of this and run it in IE it works. But when I create a regular WPF desktop app and reference the assembly I get an unusual situation: When I first add the reference (or do a clean) the ActiveXControl namespace and control appear recognized in Visual Studio. As soon as I build I get the message:

The type of namespace name 'ActiveXControl' cound not be found (are you missing a using directive or an assembly reference?)

I've tried rebuilding the control and several variations, including a WinForms project. Could someone explain why this happens and what I can do to fix it?

Answer 1

Solution was to go into the project properties and change the Target Framework from ".NET Framework 4 Client Profile" to just ".NET Framework 4." After that, it builds/runs fine.